Systems and methods for management of thrombus

ABSTRACT

An aspiration system includes an elongate tubular member having a lumen; an aspiration catheter configured to be inserted through the lumen of the elongate tubular member, and including a tubular aspiration member having a proximal end, a distal end, and a lumen, and configured to at least partially extend out of the lumen of the elongate tubular member at the distal end of the elongate tubular member; an elongate support member coupled to the tubular aspiration member and extending between a proximal end of the aspiration catheter and the proximal end of the tubular aspiration member; and an annular sealing member coupled to the tubular aspiration member and configured to create a seal against an inner surface of the elongate tubular member, when a vacuum sufficient to cause aspiration is actively applied to the lumen of the elongate tubular member.

This application is a continuation of U.S. patent application Ser. No.15/209,989, filed on Jul. 14, 2016, which is a continuation of U.S.patent application Ser. No. 14/680,017, filed on Apr. 6, 2015, now U.S.Pat. No. 9,433,427, which claims the benefit of priority to U.S.Provisional Application No. 61/976,975, filed on Apr. 8, 2014, U.S.Provisional Application No. 62/069,817, filed on Oct. 28, 2014, and U.S.Provisional Application No. 62/090,822, filed on Dec. 11, 2014, all ofwhich are incorporated herein by reference in their entireties for allpurposes. Priority is claimed pursuant to 35 U.S.C. § 120 and 35 U.S.C.§ 119.

FIELD OF THE INVENTION

The field of the invention generally relates to an aspiration system forremoving, by aspiration, undesired matter such as a thrombus from afluid carrying cavity, duct, or lumen of the body, such as a bloodvessel.

BACKGROUND

Thrombosis is managed by pharmacologic means and by interventionalmeans. These include thrombectomy, and combinations of thrombectomy withpharmacologic agents. Thrombectomy methods include breaking up and inmany cases removing thrombus from a patient having thrombosis.Thrombectomy may be mechanical or non-mechanical, and may usecatheter-based cutting or macerating elements, saline jets or aspirationof the thrombus.

A treatment method for removing undesired matter such as thrombus from ablood vessel of a patient involves use of an aspiration catheter havingelongate shaft formed with an aspiration lumen extending therein. Anaspiration catheter may also include a guidewire lumen for placement ofa guidewire, which is used to guide the aspiration catheter to a targetsite in the body. By applying a vacuum (i.e. negative pressure) to aproximal end of the aspiration lumen, for example, with a syringe havinga hub that is connected to the proximal end of the aspiration catheter,the matter can be aspirated into an aspiration port at the distal end ofthe aspiration catheter, into the aspiration lumen, and thus be removedfrom the patient.

SUMMARY OF THE INVENTION

In one embodiment, an aspiration system includes an elongate tubularmember for insertion into the vasculature of a patient, the elongatetubular member having a proximal end, a distal end, a lumen extendingfrom the proximal end to the distal end, and an inner surface defined bythe lumen; an aspiration catheter having a proximal end and a distal endand configured to be inserted through the lumen of the elongate tubularmember, the aspiration catheter including a tubular aspiration memberhaving a proximal end, a distal end, and a lumen, and configured to atleast partially extend out of the lumen of the elongate tubular memberat the distal end of the elongate tubular member and into thevasculature of the patient; an elongate support member coupled to thetubular aspiration member and extending between the proximal end of theaspiration catheter and the proximal end of the tubular aspirationmember; and an annular seal comprising at least one annular sealingmember coupled to the tubular aspiration member; a vacuum sourceconfigured for coupling to the proximal end of the elongate tubularmember; and wherein the at least one annular sealing member isconfigured to create a seal against the inner surface of the elongatetubular member, substantially preventing liquid having a viscosity ofabout 0.0025 Pascal-seconds from passing through an annular spacebetween the elongate tubular member and the tubular aspiration member ina distal to proximal direction and into the lumen of the elongatetubular member proximal to the at least one annular sealing member whena vacuum sufficient to cause aspiration of the liquid through the lumenof the tubular aspiration member and the lumen of the elongate tubularmember from the distal end of the tubular aspiration member to theproximal end of the elongate tubular member is actively applied to thelumen of the elongate tubular member at the proximal end of the elongatetubular member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of an aspiration system according to anembodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a sectional view of a standard aspiration system duringaspiration.

FIG. 4 is a sectional view of the embodiment of FIGS. 1 and 2 duringaspiration.

FIG. 5 is a sectional view of a standard aspiration system duringaspiration, with a guidewire in place through the lumens.

FIG. 6 is a sectional view of the embodiment of FIGS. 1 and 2 duringaspiration, with a guidewire in place through the lumens.

FIG. 7 is a view of the lumen cross-section in a standard aspirationcatheter or in the distal tube of the embodiment of FIGS. 1 and 2.

FIG. 8 is a view of the lumen cross section in a portion of a guidingcatheter of the embodiment of FIGS. 1 and 2.

FIG. 9 is a view of the lumen cross-section in a standard aspirationcatheter or in the distal tube of the embodiment of FIGS. 1 and 2, witha guidewire in place through the lumen.

FIG. 10 is a view of the lumen cross section in a portion of a guidingcatheter of the embodiment of FIGS. 1 and 2, with a guidewire in placethrough the lumen.

FIG. 11 is a view of an aspiration system according to an embodiment ofthe present invention during aspiration.

FIG. 12 is a perspective view of a distal section of an aspiration(thrombectomy) catheter according to an embodiment of the presentinvention.

FIG. 13 is a sectional view of an aspiration system according to anembodiment of the present invention prior to aspiration.

FIG. 14 is a sectional view of an aspiration system according to anembodiment of the present invention during aspiration.

FIG. 15 is a sectional view of an aspiration system according to anembodiment of the present invention.

FIG. 16 is a sectional view of an aspiration system according to anembodiment of the present invention.

FIG. 17 is a sectional view of an aspiration system according to anembodiment of the present invention.

FIG. 18 is a partially sectional view of an aspiration system accordingto an embodiment of the present invention.

FIG. 19 is a partially sectional view of aspiration system according toan embodiment of the present invention.

FIG. 20 is a sectional view of an aspiration system according to anembodiment of the present invention.

FIG. 21 is a sectional view of an aspiration system according to anembodiment of the present invention.

FIG. 22 is a partially sectional view of an aspiration system accordingto an embodiment of the present invention.

FIG. 23 is a partially sectional view of an aspiration system accordingto an embodiment of the present invention.

FIG. 24 is a partially sectional view of an aspiration system accordingto an embodiment of the present invention.

FIG. 25 is a perspective view of an aspiration system according to anembodiment of the present invention in use within a blood vessel.

FIG. 26A is a perspective view of an embodiment of a catheter joint.

FIG. 26B is a perspective view of a component of the catheter joint ofFIG. 26A.

FIG. 27. is a perspective view of an aspiration catheter assembled witha dipping process according to an embodiment of the present invention.

FIG. 28 is a perspective view of a distal section of an aspiration(thrombectomy) catheter according to an embodiment of the presentinvention.

FIG. 29 is a sectional view of an embodiment of a saline injectionaspiration (thrombectomy) catheter according to an embodiment of thepresent invention, with a guidewire in place through the lumens.

FIG. 30 is a plan view of a distal end of an alternative embodiment ofthe saline injection aspiration (thrombectomy) catheter of FIG. 29.

FIG. 31 is a sectional view of the saline injection aspiration(thrombectomy) catheter of FIG. 30, taken along the line 31-31.

FIG. 32 is a detail view of the saline injection aspiration(thrombectomy) catheter of FIG. 31 within circle 32.

FIG. 33 is a perspective view of a distal section of a saline aspiration(thrombectomy) catheter according to an embodiment of the presentinvention.

FIG. 34A is a cross-section of the saline injection aspiration(thrombectomy) catheter of FIG. 33, taken along the line 34A-34A.

FIG. 34B is a cross-section of the saline injection aspiration(thrombectomy) catheter of FIG. 33, taken along the line 34B-34B.

FIG. 35 is a perspective view of a proximal section of a salineaspiration (thrombectomy) catheter according to an embodiment of thepresent invention.

FIG. 36 is a perspective view of a distal section of a saline aspiration(thrombectomy) catheter according to an embodiment of the presentinvention

FIG. 37 is a perspective view of a slotted mandrel according to anembodiment of the present invention.

FIG. 38 is a cross-sectional view of the slotted mandrel of FIG. 37 asused in a dipping process according to an embodiment of the presentinvention.

FIG. 39. is a top view of a marker band during an assembly processaccording to an embodiment of the present invention.

FIG. 40. is a perspective view of a marker band during an assemblyprocess according to an embodiment of the present invention.

FIG. 41. is an end view of a marker band during an assembly processaccording to an embodiment of the present invention.

FIG. 42. is an end view of a marker band during an assembly processusing the slotted mandrel of FI. 37 according to an embodiment of thepresent invention.

FIG. 43 is a plan view of a system for aspiration according to anembodiment.

FIG. 44A is a detailed view of an aspiration monitoring system accordingto a first embodiment.

FIG. 44B is a view of an aspiration monitoring system according to asecond embodiment.

FIG. 44C is a view of an aspiration monitoring system according to athird embodiment.

FIG. 45A is a sectional view of an aspiration catheter in a blood vesselprior to contact with a thrombus.

FIG. 45B is a sectional view of an aspiration catheter in a blood vesselupon contact with a thrombus.

FIG. 45C is a sectional view of an aspiration catheter during a loss ofvacuum.

FIG. 45D is a sectional view of thrombi being aspirated through anaspiration catheter.

FIG. 46A is a graphic representation of pressure vs. time for thecondition of FIG. 45A.

FIG. 46B is a graphic representation of pressure vs. time for thecondition of FIG. 45B.

FIG. 46C is a graphic representation of pressure vs. time for thecondition of FIG. 45C.

FIG. 46D is a graphic representation of pressure vs. time for thecondition of FIG. 45D.

FIG. 47 is a diagrammatic view of a system for aspirating thrombusaccording to an embodiment of the present invention.

FIG. 48 is a diagrammatic view showing more detail of the proximalportion of the system for aspirating thrombus of FIG. 47.

FIG. 49 is a diagrammatic view of the distal end portion of the systemfor aspirating thrombus of FIG. 47.

FIG. 50A is a perspective view of an aspiration system according to anembodiment of the present invention in a first configuration.

FIG. 50B is a perspective view of the aspiration system of FIG. 50A in asecond configuration.

FIGS. 51A-51C are perspective views of an aspiration catheter accordingto an embodiment of the present invention in three differentconfigurations.

FIG. 52 is a perspective view of an aspiration catheter according to anembodiment of the present invention.

FIG. 53 is a perspective view of a thrombectomy catheter according to anembodiment of the present invention.

FIG. 54 is a perspective view of an aspiration catheter according to anembodiment of the present invention.

FIG. 55 is a perspective view of an aspiration system according to anembodiment of the present invention.

FIGS. 56A-56C are perspective views of an aspiration system according toan embodiment of the present invention in multiple configurations.

FIG. 57 is a perspective view of an aspiration system according to anembodiment of the present invention.

FIGS. 58A-58B are perspective views of an aspiration system according toan embodiment of the present invention.

FIG. 59 is a perspective view of a component of an aspiration catheteraccording to an to an embodiment of the present invention.

FIG. 60 is a perspective detail view of a portion of an aspirationcatheter according to an embodiment of the present invention.

DETAILED DESCRIPTION

Referring first to FIGS. 1 and 2, the distal portion of an aspiration orthrombectomy system 100 is shown within a blood vessel 102 of a patientwith thrombosis, including at least one thrombus 104. The blood vessel102 may comprise a vein or an artery. For example, the blood vessel 102may comprise one or more veins of the legs, including, but not limitedto the femoral or iliac veins, or one or more veins of the upperextremities, including, but not limited to the subclavian, internaljugular or axillary veins. The blood vessel 102 may also comprise theinferior vena cava or superior vena cava. The blood vessel 102 maycomprise an artery including, but not limited to a pulmonary artery, acoronary artery, a cerebral artery, an internal carotid artery, afemoral artery, an iliac artery, or a renal artery. The thrombectomysystem 100 comprises a thrombectomy catheter 106 and a guiding catheter108. The guiding catheter 108 may, for example, have an outer diameterof 6 French, an inner lumen diameter of approximately 0.183 cm (0.072inches), and have a total length of approximately 100 cm. Thethrombectomy catheter 106 is configured to be placed through the innerlumen 110 of the guiding catheter 108. The guiding catheter 108 maycomprise a composite extruded and braided tubular structure, which hassufficient flexibility and pushability to reach a target area 112. Theguiding catheter 108 may also have a pre-shaped tip. For example the tipshape may aid in cannulating coronary arteries. The thrombectomycatheter 106 comprises a distal tube 114 which is configured to beextendable out of the inner lumen 110 of the guiding catheter 108, suchthat a distal end 116 of the distal tube 114 can be advanced a desiredlength into the blood vessel 102 so that it can be placed adjacent thetarget area 112. The proximal end 118 of the distal tube 114 isconfigured to remain within the inner lumen 110 of the guiding catheter108, for example, at a region near the distal end 120 of the guidingcatheter 108. In some embodiments, the thrombectomy catheter 106includes a radiopaque marker 101, which may comprise a band secured tothe thrombectomy catheter, and made from radiodense material, such asplatinum, gold, or other similar materials. In some embodiments, thedistal tube 114 may be formed of polymeric materials containingradiopaque material, such as titanium dioxide (TiO₂).

A sealing member 124 is carried by the proximal end 118 of the distaltube 114, and may comprise, for example, an annular seal attached to anouter cylindrical surface 122 of the distal tube 114. The thrombectomycatheter 106 also comprises a support member 126, for example a wire, ahypo tube, or a composite shaft, which is secured to the distal tube 114by adhesive, mechanical attachment or other manners described herein.The support member 126 may be relatively stiff and may have a relativelysmall outer diameter so that it does not block the lumen 130 of thedistal tube 114. The sealing member 124 is configured to seal off anannulus 142 between the distal tube 114 and an inner surface 123 definedby the inner lumen 110 of the guiding catheter 108 so that an extendedlumen 128 is created, at least when a negative pressure gradient isplaced between the proximal end 144 (FIGS. 4 and 6) of the guidingcatheter 108 and the distal end 116 of the distal tube 114. The negativepressure gradient may result by coupling a vacuum source 146 to theproximal end of the guiding catheter 108. For example, a y-connector 148may be sealingly coupled to the proximal end 144 of the guiding catheter108, and the support member 126 may extend through the y-connector 148and be sealed by the proximal seal 150 (e.g. hemostatic valve) of they-connector 148. The vacuum source 146 may be coupled to the side port152 (e.g. luer) of the y-connector 148. In some embodiments, the vacuumsource 146 may comprise a 20 ml syringe, 30 ml syringe, or a largersyringe, that is lockable in its evacuated condition. An example is theVacLok® syringe sold by Merit Medical Systems, Inc. of South Jordan,Utah. In some embodiments, the syringe may be attached to the side port152 of the y-connector 148 via extension tubing known in the art. Inuse, when the distal end 116 of the distal tube 114 is extended out ofthe distal end 120 of the guiding catheter 108 into the vasculature andadjacent a thrombus 104, and the sealing member 124 is sealingly locatedwithin the inner lumen 110 of the guiding catheter 108, the negativepressure gradient caused by the application of the vacuum source 146causes the thrombus 104, or at least a portion thereof, to be aspiratedthrough the extended lumen 128. While being aspirated, the thrombus 104,or a portion thereof, first enters the lumen 130 of the distal tube 114and then enters the lumen cross-section 154 a, 154 b of the inner lumen110 of the guiding catheter 108, not already taken up by the supportmember 126 (FIG. 8), or by the support member 126 and a guidewire 134(FIG. 10), if a guidewire is left in place within the lumens 110, 130.The seal created by the sealing member 124 assures that blood 132 (FIGS.1 and 2) will not enter into the extended lumen 128 (the combination oflumen 130 and the lumen cross-section 154 of the inner lumen 110)through location A.

Blood has a non-Newtonian viscosity, which is known to vary depending onthe shear rate the blood experiences. The mean viscocity of blood canalso be varied by factors including the amount of heparinization, oranti-coagulation, employed during an interventional procedure, which mayinclude a thrombectomy procedure. Viscosities of around 0.0025pascal-seconds (2.5 centipoise) have been measured in heparinized blood,and as heparinization may lower normal blood viscosity, embodiments of asealing member 124 presented herein substantially prevent a liquidhaving a viscosity as low as 0.0025 pascal-seconds from passing throughthe annular space between the guiding catheter 108 and the distal tube114 in a distal to proximal direction and into the inner lumen 110 ofthe guiding catheter 108 proximal to the sealing member 124 when asufficient vacuum pressure is applied to the inner lumen 110 of theguiding catheter 108 to cause at least some aspiration. In someembodiments, the sufficient vacuum pressure may be about −34,474 pascal(−5 pounds per square inch) or lower. In some embodiments, thesufficient vacuum pressure may be about −46,662 pascal (−6.8 pounds persquare inch) or lower. In some embodiments, the sufficient vacuumpressure may range between about −82,737 pascal (−12 pounds per squareinch) and about −95,526 pascal (−14 pounds per square inch). In someembodiments, the sufficient vacuum pressure may be about −89,631 pascal(−13 pounds per square inch).

FIG. 11 illustrates the fluid flow 156 (e.g. blood, thrombus, maceratedthrombus) out of the proximal end 118 of the distal tube 114 (lumen 130)and through the inner lumen 110 of the guiding catheter 108. In theembodiment of the thrombectomy system 100 illustrated in FIGS. 1 and 2,the distal tube 114 has a lumen 130 configured for tracking over theguidewire 134. The guidewire 134 (e.g. 0.014″ coronary guidewire) may beused to guide the thrombectomy catheter 106 through the blood vessel102, with the lumen 130 of the distal tube 114 acting as asingle-operator exchange lumen. In some embodiments, the length of thislumen 130 may be between 5 cm and 35 cm. In some embodiments, it may bebetween 10 cm and 30 cm. In some embodiments, it may be between 15 cmand 25 cm. In some embodiments, it may be about 25 cm. As illustrated inFIG. 12, the distal tube 114 may have a skive 158 at its distal end 116and/or a skive 160 at its proximal end 118. The skives 158, 160 mayserve at least two purposes. First they aid in the tracking of thedistal tube 114 and thus the thrombectomy catheter 106 through the bloodvessel 102, including any thrombus 104 or atherosclerotic plaque (notshown), past the distal end 120 of the guiding catheter 108, and in andout of the y-connector 148, including the proximal seal 150. Second, theskives 158, 160 increase the cross-section area at the entry (or exit)points of the lumen 130 of the distal tube 114, thus lowering resistanceto flow, and allowing, for example, relatively larger pieces or portionsof thrombus to enter the lumen 130. The distal tube 114 in FIG. 12 isdepicted in a slightly curved state so that the openings 162, 164 ateither end of the lumen 130 face the viewer, so that the skives 158, 160may be better appreciated.

Returning to FIG. 11, the sealing member 124 is shown as an annular sealwith a distally facing lip 166. An annular concavity 167 extendscircumferentially around the distal tube 114 between the distally facinglip 166 and the outer cylindrical surface 122 of the distal tube 114. Insome embodiments, the sealing member 124 may be made from a number ofelastomeric materials including silicone, EPDM, polyurethane, orthermoplastic elastomers, such as PEBAX or Santoprene®. The thin-walledconstruction of the distal tube 114 allows a finite gap G between thedistal tube 114 and the inner lumen 110 of the guiding catheter 108,while still maintaining a relatively large lumen 130 in the distal tube114, in some embodiments as large as about 0.152 cm (0.060 inches) orlarger (for a 6F guiding catheter compatible thrombectomy catheter 106).In some embodiments, the gap G is 0.003″ or more on each side, and thethin lip 166 may have a thickness T of about 0.000635 cm (0.00025inches) to about 0.00508 cm (0.0020 inches). In other embodiments, thethickness T may be between about 0.0019 cm (0.00075 inches) and about0.0038 cm (0.0015 inches). On other embodiments, the thickness T may bebetween about 0.00254 cm (0.001 inches) and about 0.00317 cm (0.00125inches). With a gap G on the order of 0.0076 cm (0.003 inches) or moreper side, there would be a risk of some movement of thrombus ormacerated thrombus through the annulus 142 in direction d, due toagitation, and perhaps into the blood vessel 102, creating a risk ofembolization of a loose thrombus. However, the addition of the distallyfacing lip 166 allows the annulus 142 to be completely sealed wheneverthe vacuum source 146 (FIGS. 4 and 6) is applied, causing suction withinthe inner lumen 110 of the guiding catheter, and thus a pressure P₂proximal to the distally facing lip 166 that is less than the pressureP₁ distal to the distally facing lip 166. Because the distally facinglip 166 is made from a flexible material, and/or has a relatively smallthickness T, the positive pressure gradient from the P₁ (distal) side tothe P₂ (proximal side) (P₁−P₂>0) will cause the distally facing lip 166to be forced against the inner wall 168 of the guiding catheter 108,thus sealing it. The maximum outer diameter of the distally facing lip166 may actually be smaller than the inner diameter of the inner lumen110 of the guiding catheter 108, because it will flex (e.g., by momentM) from a first configuration (FIG. 13) to a second configuration (FIG.14) when activated by the positive pressure gradient (ΔP=P₁−P₂), inorder to seal off the annulus 142. The benefit of having a distallyfacing lip 166 whose maximum outer diameter is smaller than the innerdiameter of the inner lumen 110 of the guiding catheter 108 (when notactivated by pressure), is that during tracking of the thrombectomycatheter 106, when the vacuum source 146 is not being applied, there isno seal between the distally facing lip 166 and the inner wall 168 ofthe guiding catheter 108, and thus there is less axial friction, thusmaking it easier to track and slide the thrombectomy catheter freely(longitudinal translation), providing both low axial resistance tomotion (less drag), and high precision of motion (better “feel”). Thus,the distally facing lip 166 only expands when it is needed (i.e. duringaspiration). In some embodiments, the distal facing lip 166 may be madeusing a dipping process. In some embodiments, the dipping process may bea polyurethane dipping process. In some embodiments the distally facinglip 166 may be made from non-elastomeric materials, such polyolefins,nylon, as the pressure-activated sealing does not require elastomericcompression. In some embodiments, the distally facing lip 166 may bebonded to the distal tube 114 with adhesive, epoxy, or by thermalbonding methods. In some embodiments, the seal should be liquid tight,or water tight (saline tight), and in some embodiments need not be airtight (gas tight). In some cases liquid tight may be defined as notallowing any substantial amount of blood to pass through the annulus142. The sealing may be aided by blood viscosity, the length of theannulus 142 (distal to the sealing member 124), and the dimension of thegap G (FIG. 11). For example, a higher blood viscosity, longer annulus142 length, and a smaller gap G dimension each serve alone or incombination to increase the sealing capacity (decrease the possibilityof fluid passage throught the annulus 142).

In some embodiments, the distal facing lip 166 is configured to maintaina seal when a positive pressure gradient (ΔP=P₁−P₂) of about 46,662pascal (350 mm Hg) or higher is maintained. In some embodiments, theaspiration pressure may be maintained using a vacuum pump as the vacuumsource 146. In some embodiments, the vacuum pump provides a relativelyconstant pressure gradient of about 46,662 pascal (350 mm Hg) to about53,328 pascal (400 mm Hg). In some embodiments, a 20 ml to 60 ml syringeis evacuated in order to serve as the vacuum source 146. In someembodiments, a 30 ml syringe is evacuated in order to serve as thevacuum source 146. In some embodiments, the evacuated 30 ml syringeprovides a plateau pressure gradient of about 75,993 pascal (570 mm Hg)to about 89,626 pascal (670 mm Hg). As described, heparinized bloodtends to have a viscosity of about 0.0025 pascal-seconds (2.5 cP) orhigher. In some embodiments, the distally facing lip 166 is configuredto seal against the inner wall 168 of the guiding catheter 108 so that a0.0025 pascal-seconds liquid will not significantly pass distal toproximal when a distal to proximal positive pressure gradient (ΔP=P₁−P₂)of 46,662 pascal (350 mm Hg) is applied. In some embodiments, thedistally facing lip 166 is configured to not seal against the inner wall168 of the guiding catheter and thus not stop the passage of a liquidfrom proximal to distal (i.e. through the annulus 142) when a proximalto distal positive pressure gradient (ΔP=P₂−P₁) of 46,662 pascal (350 mmHg) is applied.

FIG. 6 illustrates the aspiration flow path and FIGS. 9 and 10illustrate the lumen cross-sections 136 b, 154 b if the guidewire 134 isleft in place during aspiration. FIG. 4 illustrates the aspiration flowpath and FIGS. 7 and 8 illustrate the lumen cross-sections 136 a, 154 aif the guidewire 134 is not left in place during aspiration, forexample, if it is removed. Starting with this latter “no guidewire”condition, FIG. 7 illustrates a lumen cross-section 136 a, which mayrepresented by a lumen 138 of a standard thrombectomy catheter 140 inFIG. 3, or by the lumen 130 of the thrombectomy catheter 106 of anembodiment of the present invention in FIG. 4. A comparison between theflow characteristics of the standard thrombectomy catheter 140 and theembodiment of the thrombectomy system 100 of FIGS. 1 and 2 is presentedbelow.

The standard Hagen-Poiseuille Law flow equation used to calculate theflow of fluids (e.g. blood and/or macerated thrombus) is:

$Q = \frac{\Delta \; P\; \pi \; D^{4}}{128\; µ\; L}$

where L is the length of a particular flow path,

ΔP is the pressure gradient between one end of the flow path and theother end of the flow path,

D is the diameter of the flow path, and

μ is the viscosity of the fluid.

Because luminal cross-sectional areas are often non-circular, the termHydraulic Diameter (D_(H)) is often substituted for diameter D.Hydraulic Diameter (D_(H)) represents the effective diameter of acircular cross-section that behaves the same as a non-circularcross-section. The Hydraulic Diameter (D_(H)) equation is:

$H_{D} = \frac{4A}{p}$

where A is the cross-sectional area of the lumen, and

p is the summation of the perimeter of all of the luminal walls oncross-section.

Combining these two equations, the standard Hagen-Poiseuille Law flowequation for a particular Hydraulic Diameter (D_(H)) is:

$Q = \frac{\Delta \; P\; \pi \; D_{H}^{\underset{\_}{4}}}{128\; µ\; L}$

Using the Ohm's Law analogy for fluid flow, produces the equation:

$Q = \frac{\Delta \; P}{R}$

where R is the Resistance (to fluid flow), given thus by the equation:

$R = \frac{128\; µ\; L}{\pi \; D_{H}^{4}}$

As differing lumen cross-sections 136, 154 are arrayed serially in thesystems being discussed, the serial resistance equation will be used,the equation being:

R _(T) =R ₁ +R ₂ +R ₃+ . . .

where R_(T) is the total resistance, and

R₁, R₂, R₃, etc. are individual serial resistances.

The intention is to compare the total (flow) resistance of a firstthrombectomy system (R_(T1)) with the total resistance of a secondthrombectomy system (R_(T2)). Thus, the constant 128/π can be removedfrom the comparative term, leaving μL/D_(H) ⁴. Additionally, thoughblood is non-Newtonian, and thus may exhibit variance in viscosity atdifferent shear rates, the variation of the effective viscosity of athrombus/macerated thrombus/blood slurry is not expected to besignificant among the different lumen conditions described. Therefore,the viscosity (μ) term may also be removed from the comparative term.This leaves a comparative term of:

Comparative Flow Resistance(R _(C))=L/D _(H) ⁴

Comparative Flow Resistance (R_(C)) can be calculated using the units(1/cm³).

Returning to the standard thrombectomy catheter 140 of FIG. 3, theentire length L₁ of the catheter in some models is about 140 cm and hasa circular cross-sectional diameter D₁ of its lumen 138 of about 0.11 cm(0.042 inches). Because the lumen 138 is circular, 0.11 cm (0.042inches) is also the Hydraulic Diameter (D_(H)). In comparison, theembodiment of the thrombectomy system 100 of FIG. 4, includes a firstlength L₂ representing the length of the distal tube 114 of thethrombectomy catheter 106, and in one embodiment L₂ is about 25 cm. Inthis particular embodiment, the lumen 130 of the distal tube 114 mayhave a circular cross-sectional diameter D₂ of its lumen 130 of about0.15 cm (0.060 inches) The thrombectomy system 100 is inserted through aguiding catheter 108 having a lumen inner diameter of about 0.183 cm(0.072 inches) and a length of about 100 cm, thus having a flow lengthL₃ of about 100 cm. Assuming a support member 126 embodiment comprisinga substantially rectangular cross-section stainless steel wire having aminor dimension of about 0.0305 cm (0.012 inches) and a major dimensionof about 0.0508 cm (0.020 inches), the Comparative Flow Resistance(R_(C)) may be calculated for the standard thrombectomy catheter 140 andthe thrombectomy system 100 in their “no guidewire” configurations ofFIGS. 3 and 4, respectively. Table 1 demonstrates that the ComparativeFlow Resistance (R_(C1)) of the thrombectomy system 100 is only about15% the Comparative Flow Resistance (R_(C2)) of the standardthrombectomy catheter 140.

TABLE 1 R_(c1) R_(c2) Condition (1/cm³) (1/cm³) R_(c1)/R_(c2) NoGuidewire (FIGS. 3 and 4) 160,822 1,080,926 0.15 Guidewire (FIGS. 5 and6) 320,704 1,080,926 0.30

The standard thrombectomy catheter 140 in FIG. 5 has a guidewire 134within the length of its lumen 138. The thrombectomy system 100 of FIG.6 has a 0.014″ diameter guidewire 134 (0.036 cm) within the length ofthe lumen 130 of the distal tube 114 and the inner lumen 110 of theguiding catheter 108. The thrombectomy system 100 of FIG. 6 also has asupport member 126 having cross-sectional dimensions of 0.0305 cm×0.0508cm (0.012 inches×0.020 inches) within the length of the inner lumen 110of the guiding catheter 108. Table 1 demonstrates that the ComparativeFlow Resistance (R_(C1)) of the thrombectomy system 100 is only about30% the Comparative Flow Resistance (R_(C2)) of the standardthrombectomy catheter 140. This means that at a particular negativepressure gradient, the aspiration flow rate through the thrombectomysystem 100 can be as much as 3.33 times more than the aspiration flowrate through the standard thrombectomy catheter 140.

A test was performed wherein a 30 ml vacuum was locked onto anextraction syringe, and sealed with a closed stopcock. The extractionsyringe and stopcock were then attached to a catheter/catheter systemand the tip of the catheter placed in a beaker of water. The stopcockwas then opened and the time was measured for the 30 ml syringe to fillwith water. The data is listed in Table 2.

TABLE 2 Time to System fill 30 ml syringe (seconds) Medtronic Export AP25 Prototype with 25 cm long, 0.147 cm (.058 7.2 inches) ID distal tube,and 0.0305 cm × 0.0508 cm (0.012 inches × 0.020 inches) support memberin 0.183 cm (.072 inches) ID × 100 cm long guiding catheter - distaltube extending 25 cm from guiding catheter Prototype with 25 cm long,0.147 cm (.058 6.7 inches) ID distal tube, and 0.0305 cm × 0.0508 cm(0.012 inches × 0.020 inches) support member in 0.183 cm (.072 inches)ID × 100 cm long guiding catheter - distal tube extending 5 cm fromguiding catheter

Published data using a similar 30 ml syringe water vacuum test showsPeak Extraction Rate (ml/sec) for several thrombus aspiration catheters.The peak extraction rate ranged from 0.94 ml/second to 1.71 ml/second(Table 3). Published in “Comparison of Dimensions and Aspiration Rate ofthe Pronto® V3, Pronto® LP, Export® XT, Export® AP, Fetch®, Xtract™,Diver C.E.™ and QuickCat™ Catheters” (ML1623 Rev. F 12/09 c2009 VascularSolutions, Inc.) In comparison, the prototype thrombectomy system 100tested in the two conditions of Table 1, demonstrated an averageextraction rate of 3.6 ml/second to 4.0 ml/second, 2.1 to 2.3 times thepeak extraction rate of the highest performing catheter (Pronto V3) inthe published data set. And it should be mentioned that the designs ofthe thrombus aspiration catheters of the Table 3 test data are such thatthere is no guidewire within their lumen (as in FIG. 3) duringaspiration, and the prototype thrombectomy system 100 tested also didnot have a guidewire within its lumens during testing (as in FIG. 4). Inuse, for aspirating body fluids and materials such as blood andthrombus, embodiments of the thrombectomy system 100 of the presentinvention have significantly higher potential to remove thrombus morequickly and more completely than a standard thrombectomy catheter 140,such as those represented in the published data. The amount of vacuumpresent at the lumen 130 at the distal end 116 of the distal tube 114may be up to twice that (or more) of the amount of vacuum present at thedistal tip of the lumen 138 of a standard thrombectomy catheter 140,which attests to larger forces pulling the thrombus 104 into the lumen130.

TABLE 3 Peak Extraction Rate (ml/sec) of water System evacuated by 30 mlsyringe Pronto ® V3 (Vascular Solutions, Inc.) 1.71 Pronto ® LP(Vascular Solutions, Inc.) 0.94 Export ® XT (Medtronic, Inc.) 1.27Export ® AP (Medtronic, Inc.) 1.44 Fetch ® (Medrad/Possis) 1.55 Xtract ™(Volcano/Lumen Biomedical) 1.24 Diver C.E. ™ (Invatec) 1.04 QuickCat ™(Spectranetics) 1.11

FIG. 15 illustrates an embodiment of the thrombectomy system 100,wherein the thrombectomy catheter 106 includes a sealing member 124 thatis an o-ring 174 having a custom cross-section having a wider baseportion 170 having a width W and a wiper blade portion 172 having awidth w, that is smaller than width W. Though the maximum outer diameterof the o-ring 174 of this embodiment should be larger than the innerdiameter of the inner lumen 110 of the guiding catheters 108 with whichit is compatible (for sealable coupling), the thinner the width w of thewiper blade portion, the less drag and the greater feel is achieved. Thedistal tube 114 includes an annular groove 180, having a width largeenough to seat the base portion 170 of the o-ring 174. In FIG. 15, thedistal tube 114 of the thrombectomy catheter 106 is shown with a distalskive 158, but without a proximal skive (160 in FIG. 12). As mentioned,numerous combinations of the skives 158, 160 are contemplated and arenot limiting. FIG. 16 illustrates a closeup of an embodiment of thethrombectomy system 100, wherein the thrombectomy catheter 106 includesa sealing member 124 that is an o-ring 174 having an x-shapedcross-section 178. FIG. 17 illustrates a closeup of an embodiment of thethrombectomy system 100, wherein the thrombectomy catheter 106 includesa sealing member 124 that is an o-ring 174 having a circularcross-section 176. Numerous other o-ring cross-sections arecontemplated. The annular groove 180 has enough width to seat thecorresponding o-ring cross-sections 176, 178 of the embodiments of FIGS.16 and 17. A lip, such as the distally facing lip 166 of the embodimentof the thrombectomy system 100 of FIG. 11, or a seal, such as the o-ring174 having a wiper blade portion 172 of FIG. 15, may have severaloptional embodiments in which their maximum outer diameter isconstructed to different diameters in relation to the inner diameter ofthe guiding catheter 108. For example, in some embodiments, the outerdiameter may be in rubbing relation to the inner diameter of the guidingcatheter 108. In some embodiments, the outer diameter may be in touchingrelation to the inner diameter of the guiding catheter 108. In someembodiments, the outer diameter may be in close clearance relation tothe inner diameter of the guiding catheter 108. In some embodiments, theouter diameter may be in a non-touching relation to the inner diameterof the guiding catheter 108. In some embodiments, there may me multiplefeatures, having a combination of these relationships (rubbing,touching, etc.). In some embodiments, the sealing member 124 may be aninflatable balloon, whose diameter and/or inflation pressure may becontrolled.

FIG. 18 illustrates an embodiment of a thrombectomy system 100 havingmultiple sealing members 124, denoted by 124 a, 124 b, 124 c, 124 d, 124e, and 124 f. In some embodiments, the sealing members 124 a-f may beannular seals, such as any of the embodiments described herein. In someembodiments, the guiding catheter 108 may be from a different or unknownsupplier and it may be difficult to know the true inner diameter of theinner lumen 110 along a significant length of the distal portion of theguiding catheter 108. However, it may be possible for the user tomeasure the inner diameter at a distal portion 182 of the guidingcatheter 108 (for example, using sterile pin or plug gauges). Themultiple sealing members 124 a-f make it possible to adjust the distanceDE that the inner tube 114 extends from the guiding catheter 108, whileassuring a sealing relationship between the particular sealing member124 a-f and the inner diameter of the guiding catheter 108 at the distalportion 182. For example, when sealing member 124 a is sealingly engagedwith the inner diameter of the guiding catheter 108 at the distalportion 182, DE is much shorter than when sealing member 124 f issealingly engaged with the inner diameter of the guiding catheter 108 atthe distal portion 182. Thus, in use by the physician, the distal end116 of the distal tube 114 can be brought into ideal position inrelation to the thrombus 104 (FIGS. 1 and 2), for example, just proximalto the thrombus 104. Additionally, the short axial length of contact ofeach of the sealing members 124 a-f with the inner wall 168 of theguiding catheter 108 summed together is much less than if the entireouter cylindrical surface 122 of the distal tube 114 were a cylindricalseal, and this lowers the drag and increases the feel. Multiple axialspaces 184 a-e, located between the sealing members 124 a-f, representthe majority of the length of the distal tube 114, and thus gap G can belarge enough (e.g. 0.0076 cm (0.003 inches) or greater per side) so thateven in tortuosities of the blood vessel 102, where the catheters may becurved or angled, the drag is not unacceptably increased and the feel isnot unacceptably decreased.

FIG. 19 illustrates an embodiment of a thrombectomy system 100 havingone or more sealing members 124 comprising a hydrogel 186 annularlyattached around the outer cylindrical surface 122 of the distal tube 114of the thrombectomy catheter 106. In some embodiments, the maximum outerdiameter of the sealing member 124 comprising a hydrogel 186 may be lessthan the inner diameter of the inner lumen 110 of the guiding catheterwhen the hydrogel is in a non-hydrated or substantially non-hydratedstate. The maximum outer diameter of the sealing member 124 comprising ahydrogel 186 may become greater than the inner diameter of the innerlumen 110 of the guiding catheter when the hydrogel is in a partiallyhydrated, substantially hydrated, or fully hydrated state. This featureallows the thrombectomy catheter 106 to be advanced with little dragdown the guiding catheter 108 while the sealing member 124 comprising ahydrogel 186 is becoming hydrated. As the sealing member 124 comprisinga hydrogel 186 becomes substantially hydrated, the sealing member 124will likely be already placed at the location of choice in relation tothe distal end 120 of the guiding catheter 108. In this position, thelarger maximum outer diameter of the sealing member 124 will sealagainst the inner wall 168 of the inner lumen 110 of the guidingcatheter. In some embodiments, the hydrogel 186 has high lubricity inorder to allow movement with minimal drag while the sealing member 124is in sealing relationship against the inner wall 168 of the inner lumen110 of the guiding catheter. In some embodiments, the high lubricity isachieved by the hydrogel having a higher water holding capacity. In someembodiments, the hydrogel 186 has relatively lower lubricity in order tominimize accidental axial movement of the sealing member 124 in relationto the guiding catheter. In some embodiments, the high lubricity isachieved by the hydrogel having a lower water holding capacity. In someembodiments, the hydrogel comprises p-HEMA.

FIG. 20 illustrates an embodiment of a thrombectomy system 100 havingone or more sealing members 124 coupled to the proximal end 118 of thedistal tube 114 of the thrombectomy catheter 106. In some embodiments,the one or more sealing member 124 is secured to the outer cylindricalsurface 122 of the distal tube 114. In some embodiments, the sealingmember 124 is a cone-shaped or bowl-shaped membrane 190 configured toseal against the inner wall 168 of the guiding catheter 108 at the wipeend 188.

FIG. 21 illustrates an embodiment of a thrombectomy system 100 having asealing member 124 which is formed from the proximal end 118 of thedistal tube 114 of the thrombectomy catheter 106. In some embodiments,the sealing member 124 is formed by flaring the proximal end 118 of thedistal tube 114, so that a seal ring 192 is created, for sealing againstthe inner wall 168 of the guiding catheter 108.

FIG. 22 illustrates an embodiment of a thrombectomy system 100 having asealing member 124 coupled to the proximal end 118 of the distal tube114 of the thrombectomy catheter 106. In some embodiments, the sealingmember 124 may comprise a cone-shaped or bowl-shaped structure 194. Insome embodiments, the structure 194 may be formed from a tubular braid196. In some embodiments, the tubular braid 196 may be braided frommetallic wires. In some embodiments, the tubular braid 196 may bebraided from Nickel-Titanium wires. In some embodiments, the tubularbraid 196 may be heat set into a cone shape or a bowl shape. In someembodiments, the tubular braid 196 may be dip coated. In someembodiments, the tubular braid 196 may be dip coated after having beenheat set. In some embodiments, the tubular braid 196 may be dip coatedwith polyurethane. In some embodiments, the tubular braid 196 may be dipcoated with silicone. In some embodiments, the dip coating material mayform a seal ring 198 for sealing against the inner wall 168 of theguiding catheter 108. In some embodiments, the tubular braid 196 isformed so that the seal ring 198 is forced against the inner wall 168 ofthe guiding catheter 108. In some embodiments, the dip-coated, formedtubular braid 196 is sufficiently compressible that it can be pushedthrough the inner lumen 110 of a guiding catheter 108. FIGS. 20-22illustrate embodiments of a thrombectomy catheter 106 in a conditionwhen it is at least partially extended axially out of the inner lumen110 of the guiding catheter 108. In some embodiments, a stiffnesstransition member 197 (FIG. 22) may be incorporated into the distal tube114. In some embodiments, the stiffness transition member 197 maycomprise a hypo tube that is spiral cut (e.g. laser cut) with decreasingpitch moving distally. A number of other methods known in the art may beused to create a transition in stiffness, such as use of compositematerials, a transition of polymeric materials, or transitioning braidsor coils.

FIG. 23 illustrates an embodiment of a thrombectomy system 100 having asealing member 124 which is the proximal end 118 of the distal tube 114of the thrombectomy catheter 106. In some embodiments, the entire distaltube 114 comprises a windsock-like-member 200 having a tapered portion204. The proximal end 118 has an increased diameter and is supportedradially by a stent section 202. In some embodiments, the stent section202 is a coil. In some embodiments, the stent section 202 is a lasermachined metal tube. In some embodiments, the stent section 202 is atubular braid.

FIG. 24 illustrates an embodiment of a thrombectomy system 100 having asealing member 124 which is coupled to the proximal end 118 of thedistal tube 114 of the thrombectomy catheter 106. A structure 206comprising two or more fingers 208 a-d is secured to the proximal end118 of the distal tube 114. In some embodiments, the structure 206 iswelded or secured using other methods to the support member 126. In someembodiments, the structure 206 is flared outwardly towards the proximalend, leading to a sealing ring 212. In some embodiments, the structure206 includes a covering 210 over the fingers 208 a-d. In someembodiments, the covering 210 is a membrane.

FIG. 25 illustrates an embodiment of a thrombectomy system 100 of thepresent invention being used in conjunction with the deployment of astent 214. In the method for performing this procedure with thethrombectomy system 100, the interventionalist (physician) places aguiding catheter 108 into the blood vessel 102. For example, theinterventionalist may place the distal end 120 of the guiding catheter108 into the ostium of a coronary artery. The interventionalist may nextplace a guidewire 134 across an atherosclerotic lesion 218, which may ormay not have thrombus 104. The interventionalist next tracks anembodiment of the thrombectomy catheter 106 of the present inventionover the guidewire 134 and through the guiding catheter 108, until thedistal end 116 of the distal tube 114 exits the guiding catheter. Theinterventionalist the tracks the distal end 116 of the distal tube to atarget area 112, for example, just proximal to the location of theatherosclerotic lesion 218. The sealing member 124 is positioned withinthe guiding catheter 108, so that it will be sealingly coupled to theguiding catheter at least while aspiration is being performed. Theinterventionalist then tracks a dilatation catheter 216 over theguidewire 134, through the guiding catheter 108, and across theatherosclerotic lesion 218. The vacuum source 146 (FIGS. 1 and 2) iscoupled to the side port 152 of the y-connector 148, and the stent 214is expanded by the dilatation balloon of the dilatation catheter 216while the thrombectomy system performs aspiration. This lowers thepossibility that residual thrombus (clot) is carried downstream, causingpotential complications. It also lowers then possibility that residualthrombus remains trapped between the stent 214 and the now dilatedatherosclerotic lesion 218. When the interventionalist deems the resultsatisfactory, the interventionalist takes final fluoroscopic (or other)images, and then removes the devices.

FIGS. 26A-26B illustrate an attachment joint 228 and method forjoining/coupling the support member 126 to the distal tube of athrombectomy catheter 106 according to an embodiment of the presentinvention. A tapered half-pipe member 220 comprising a partial cylinderis secured at its large end 222 to the proximal end 118 of the distaltube 114 by adhesive, epoxy, welding, soldering, embedding or otherattachment methods. The small end 224 of the tapered half-pipe member220 is secured to the support member 126 by adhesive, epoxy, welding,soldering, embedding or other attachment methods. Though the skives 158,160 are not pictured in FIG. 26, they are compatible with this joiningembodiment and method. The tapered half-pipe member 220 allows for agradual transition that provides an open area 226, so that flow is notcompromised. In some embodiments, the outer radius 227 of the taperedhalf pipe member 220 is configured to substantially match the innerdiameter of the distal tube 114. In some embodiment, the inner radius229 of the tapered half pipe member 220 is configured to substantiallymatch the outer diameter of the distal tube 114. These embodimentsenable a close fit and thus a relatively low profile.

FIG. 27 illustrates a dipping process for an attachment joint includingbut not limited to the attachment joint 228 of FIG. 26. After theattachment joint 228 is assembled, a first dipping step 230 is performedover the majority of the length of the distal tube 114. In someembodiments, the distal tube 114 may comprise a lubricious inner tubelayer, such as PTFE, and a spring coil inner layer around the PTFE innertube layer. In some embodiments, a medium durometer dipping material,such as polyurethane or PEBAX, is applied to the distal tube. In someembodiments, the medium durometer material may have a durometer of about63D. A second dipping step 232 is performed with a low durometermaterial, such as polyurethane of PEBAX, to form a “Soft” tip 234. Insome embodiments, the low durometer material may have a durometer ofabout 55D. A third dipping step 236 is performed with a high durometermaterial over the attachment joint 228. In some embodiments, the thirddipping step 236 is performed over most or all of the length of thesupport member 126. In some embodiments, the high durometer material mayhave a durometer of about 72D. The result is a stiff, pushable catheter106 that has a smooth transition at the attachment joint 228, a flexibledistal tube 114 for tracking through the blood vessel 102 (FIGS. 1, 2and 25) and a soft tip 234 for atraumatic characteristics within theblood vessel 102. A maximized lumen 130 cross-section area may beachieved in any of the embodiments resented herein by minimizing wallthickness and/or minimizing the thickness of any coating. Ultra-thinwall hypo tubes or polyimide tubes may be used in some embodiments. Adip coating of less than about 0.005 cm (0.002 inches) may be applied,and may include polyurethane. A dip coating of less than about 0.0025 cm(0.001 inches), or about 0.0018 cm (0.0007 inches) may be applied, andmay include polyurethane.

FIG. 28 illustrates an embodiment of a thrombectomy catheter 106 of thethrombectomy system 100 having a sealing member 124 that is radiallycompressed over a compressible section 242 of the distal tube 114 duringdelivery through the guiding catheter 108 (FIG. 1). The compressiblesection 242 is held in a compressed state by a delivery sheath 238. Insome embodiments, the delivery sheath 238 has a sheath push and pull rod240 coupled to a portion thereof. In use, the thrombectomy catheter 106is delivered through the guiding catheter 102 and into the blood vessel102 by pushing the support member 126 and/or the sheath push and pullrod 240. When the distal end 116 of the distal tube 114 of thethrombectomy catheter 106 is located adjacent the target area 112 andthe proximal end 118 of the distal tube 114 is within the inner lumen110 of the guiding catheter 108 (FIG. 2), traction (tension) is appliedon the sheath push and pull rod 240 while compression is applied on thesupport member 126, thus causing the delivery sheath 238 to be pulledproximally, and removed from the compressible section 242 of the distaltube 114, thus allowing the compressible section 242 to expand, and sealagainst the inner wall 168 (FIG. 15) of the guiding catheter 108. Insome embodiments, the delivery sheath 238 may be retracted completelyand removed completely from the guiding catheter 108. Though a guidewire134 is not depicted in FIG. 28, this embodiment, like the otherembodiments, may be used with a guidewire 134, as known in the art. Insome embodiments, the support member 126 may be coupled to the distaltube 114 via a ring 244. In some embodiments, the ring 244 may be closerto the distal end 116 of the distal tube 114 than the proximal end 118.

Saline Injection Aspiration

FIG. 29 illustrates a thrombectomy system 300 which incorporates thehigh pressure injection of a liquid, for example sterile salinesolution, in order to macerate and aspirate thrombus 104 (FIG. 1). Aguiding catheter 108 and a y-connector 148 having a proximal seal 150and a sideport 152 are coupled to a vacuum source 146, as described inrelation to the prior embodiments. A thrombectomy catheter 306 comprisesa distal tube 314 having a distal end 316 and a proximal end 318, theproximal end 318 incorporating one or more sealing members 324 forsealing off an annulus 342 between the guiding catheter 108 and thedistal tube 114, as described in relation to the prior embodiments. Thedistal tube 314 has an aspiration lumen 330. A support/supply tube 368,having a lumen 370, is coupled to the distal tube 314. Thesupport/supply tube 368 serves the same purpose as the support member126 of the prior embodiments, but is also a conduit (via the lumen 370)for high pressure saline, which is injected from the proximal end 372 tothe distal end 374. The saline is supplied from a saline source 376(e.g. saline bag, bottle) and pressurized by a pump 378, through asupply tube 380 and through a luer connector 382 which is connected to aluer hub 384 coupled to the support/supply tube 368. In someembodiments, the support/supply tube 368 comprises a hypo tube. In someembodiments, the support/supply tube 368 comprises stainless steel ornitinol.

Turning to FIGS. 30-32, in some embodiments, the support/supply tube 368may be coupled to the distal tube 314 by attachment materials 386, 388,including adhesive, epoxy, or melted/molded polymer materials. In someembodiments, the support/supply tube 368 has a closed distal end 394,and has one or more orifices 390 in its wall 392. In some embodiments, arapid exchange tube 398 having a guidewire lumen 396 and a distal tip408 may be coupled to the side of the distal tube 314, as seen in FIGS.30 and 31, although the embodiment of FIG. 29 is shown with theguidewire 134 extending through the aspiration lumen 330 and the innerlumen 110.

After the user tracks the thrombectomy catheter 306 through the guidingcatheter 108 and to the target area 112 in the blood vessel 102, thepump 378 is operated to inject high pressure saline through thesupport/supply tube 368. When the saline reaches the orifice (arrows400), the saline is forced through the one or more orifices 390 and intothe aspiration lumen 330. In some embodiments, the saline forms one ormore jets 402 that impinge upon in inner wall 404 of the aspirationlumen 330, adjacent the one or more orifices 390. A high pressure isthus created in the aspiration lumen 330 adjacent the skive 358, forcingthrombus 104 into the aspiration lumen 330 in a direction generallyshown by arrow 406. The thrombus 104 is then carried by the positivepressure gradient from distal to proximal from the aspiration lumen 330into the inner lumen 110 of the guiding catheter 108 and out thesideport 152 of the y-connector 148 towards the vacuum source 146. Insome embodiments, the one or more jets 402 serve to break up andmacerate the thrombus 104, aiding in its subsequent passage through thelumens 330, 110. The mixing of the saline with the broken up thrombus104 serves to lower its bulk viscosity, and thus aid in its passagethrough the catheter lumens with less resistance. In some embodiments,the one or more orifices 390 are located a distance D from the mostproximal portion 410 of a distal opening 412 formed in the aspirationlumen 330 by the skive 358. In some embodiments, the distance D betweenthe axial center of an orifice 390 and the most proximal portion 410 ofthe distal opening 412 is about 0.0508 cm (0.020 inches), or in someembodiments is 0.0508 cm±0.0076 cm (0.020 inches±0.003 inches).

FIGS. 33-34B illustrate an alternative embodiment of the support/supplytube 368, wherein the support/supply tube 368 couples to the distal tube314 at the proximal end 318 of the distal tube 314. The distal tube 314includes a wall 416 having a lumen 414. The support/supply tube 368 iscoupled to the lumen 414 so that saline supplied through thesupport/supply tube 368 then passes through the lumen 414 distally, andexits the one or more orifices 390. In some embodiments, the lumen 414may be provided by a separate polyimide tube that is embedded in thewall 416. In some embodiments, a proximally facing lip 246, for example,an annular seal extending in both a radial and proximal direction, issealingly coupled to the distal tube 314. The high pressure salineinjection through the lumen 370 of the support/supply tube 368, incombination with the vacuum source 146 (FIGS. 3-6), causes aspiration ina direction generally shown by arrow 406. The high pressure salineinjection also creates an internal pressure P_(I) within the inner lumen110 of the guiding catheter 108 that is higher than the ambient pressureP_(A) outside the distal end 120 of the guiding catheter 108. BecauseP_(I)>P_(A), the proximally facing lip 246 is forced against the innerwall 168 of the inner lumen 110 of the guiding catheter 108, sealing theannulus 142. In some embodiments, the proximally facing lip 246 is thinand made from a flexible material (as in the distally facing lip 166 ofFIG. 11), thus aiding is ability to be forced against the inner wall168. In some embodiments, other embodiments of the sealing member 124may be used, including, but not limited to, o-rings and hydrogel seals.In some embodiments, as seen in FIG. 34B, the distal end of thesupport/supply tube 368 may have an oval, elliptical or rectangularshape in order to allow a connection to the lumen 414 of the distal tube314 that does not significantly compromise the size of the aspirationlumen 330 of the distal tube 314.

FIG. 35 illustrates an embodiment of the thrombectomy catheter 306wherein the lumen 370 of the support/supply tube 368 may be decoupledfrom the luer hub 384 (FIG. 29) so that a stylet 418 may be inserteddown the lumen 370 in order to impart additional stiffness andpushability. In some embodiments, the stylet 418 comprises stainlesssteel. In some embodiments, the support/supply tube 368 is a circularcross-section hypo tube and has an outer diameter of about 0.0549 cm(0.0216 inches) and an inner diameter of about 0.0483 cm (0.019 inches).In some embodiments, the stylet 418 has a circular cross-section and hasan outer diameter of between about 0.038 cm (0.015 inches) and about0.0457 cm (0.018 inches). In some embodiments, the sytlet 418 may have ahub 420 at its proximal end, in order to aid handling of the stylet 418during insertion and removal.

FIG. 36 illustrates an embodiment of the thrombectomy catheter 306wherein the lumen 370 of the support/supply tube 368 is coupled to asmaller tube 422 within the aspiration lumen 330 of the distal tube 314.In some embodiments, the smaller tube 422 is a polyimide tube. In someembodiments, the smaller tube 422 is a tapered polyimide tube, taperingto a smaller diameter as it extends distally to its orifice 424. Thesupport/supply tube 368 is also secured to a ring 426, which in someembodiments is closer to the distal end 316 than the proximal end 318 ofthe distal tube 314. The ring 426 is also secured to the distal tube314. When the user pushes on the support/supply tube 368 at its proximalend, the force that in turn is applied to the ring 426 serves to “pull”the proximal end 318 of the distal tube 314, thus lessening the chancesof compressing or deforming it. The proximal end 318 of the distal tube314 includes an expandable section 430 which may include a tubular mesh428. The tubular mesh 428 may be encapsulated, for example by dipping inpolyurethane of silicone, in order to create a sealed aspiration lumen330 that extends from the distal end 316 to the proximal end 318. Insome embodiments, the ring 426 may be constructed from a metal material,such as stainless steel or nitinol. In some embodiments, the ring 426may include radiopaque material, such as platinum, for visualization onfluoroscopy or x-ray. The ring 426, and its use as the point ofapplication of pushing or pulling, may be incorporated into one of theembodiments of the thrombectomy catheters 106 that do not have highpressure saline injection, but only aspiration. In this case, thesupport/supply tube 368 need not be a tube or hypo tube, but may also bea solid round wire flat wire.

Because of their use of the inner lumen 110 of the guiding catheter 108as a portion of the extended lumen 128 (FIG. 2), any of the thrombectomysystems 100, 300 presented include the feature that one length (model)the thrombectomy catheter 106, 306 may be used on a variety of patientsizes and/or target area 112 depths. A single model of thrombectomycatheter 106, 306 may be adjusted to the desired depth in the bloodvessel 102 so that it is adjacent to the target area 112, but the vacuumsource 146 is still coupled at the same location, on the side port 152of the y-connector 148. A large range of models (e.g. different lengths)of the thrombectomy catheter 106, 306 is not required. In some cases,this may mean that a single model of thrombectomy catheter 106 and/or asingle model of thrombectomy catheter 306 may satisfy the majority ofthrombectomy procedures performed in a particular catheterizationlaboratory or other health care facility, thus requiring a smaller areaof shelf space.

An assembly process for an embodiment of a thrombectomy catheter 306 isillustrated in FIGS. 37-42. A slotted mandrel 440 having alongitudinally extending slot 442 is shown in FIG. 37. FIG. 38illustrates a cross-section of the slotted mandrel 440 and severalcomponents placed over it during a placement step, in the followingradial order: liner tube 444, saline lumen tube 448 having a salinelumen 446, and a support layer 450. In some embodiments, the orifice maybe pre-cut into the saline lumen tube 448 and may be aligned during theplacement step. In some embodiments, the liner tube 444 may comprisePTFE or other fluropolymers. In some embodiments, the saline lumen tube448 may comprise a polyimide tube. In some embodiments, the supportlayer 450 may comprise a tubular braid, one or more coils or a lasermachined hypo tube. The slotted mandrel 440 with the components 444,448, 450 placed over it, is dipped into a polyurethane, silicone, orother material to coat and set, during a dipping process, creating acomposite structure 445 having an outer layer 447. The slotted mandrel440 is then removed, during a removal step, and the ends of the salinelumen tube 448 may be cut clean. As seen in FIGS. 39-42, a radiopaquemarker band 452 may be incorporated as part of the assembly by bondingthe radiopaque marker band 452 to the saline lumen tube 448 with anadhesive 454 or epoxy, aligning the saline lumen tube 448 as in FIG. 42,and then completing the assembly and the dipping process as described inrelation to FIG. 38.

Clog Detection/Clot Detection

Clogging of aspiration catheters, for example by large pieces ofthrombus, is a common concern for users. Techniques to avoidclogging/choking of material within the catheter often involve rapidly,aggressively advancing the aspiration catheter or gently plucking atedges of a thrombus to insure only small pieces or portions areintroduced at a time, pieces which are small enough to not clog orocclude the aspiration lumen. When a device becomes clogged during use,the potential for inadvertent dislodgment of thrombus downstreamincreases; this is referred to as distal embolism. As aspirationprocedures of this type are often used in highly technical emergentsettings, early clog detection of the aspiration catheter for the userduring aspiration can contribute to the success of the procedure andclinical outcome. Some sources have reported that up to 50% ofaspiration catheters used get clogged during use.

Additionally, the user may have difficulty determining whether there hasbeen a loss of vacuum in the system, for example because of the syringe(or other vacuum source) being full of fluid or because of a leak in thesystem. Blood is relatively opaque and can coat the wall of the syringe,thus making it difficult to determine when the syringe becomes full.This makes it difficult to determine whether sufficient vacuum is beingapplied to the aspiration catheter. It is also difficult to determinewhether there is an air leak in the system, which can be another causefor a loss of vacuum even before the syringe becomes full of theaspirated fluid.

During the aspiration of thrombus with an aspiration catheter, it isdifficult to identify when thrombus is actively being aspirated, andwhen only blood is being aspirated. Typically it is desired to notaspirate sizable quantities of normal blood from blood vessels, becauseof the importance of maintaining normal blood volume and blood pressure.However, when tracking the tip of an aspiration catheter in proximity toa thrombus, it is difficult to know whether the aspiration catheter hasactively engaged a thrombus, whether it has aspirated at least a portionof the thrombus, or whether it is not engaged with the thrombus, and isonly aspirating blood. The use of aspiration catheters can therefore beinefficient, and cause more blood removal than desired, causing a userto minimize the length of the therapy and in severe cases necessitatingblood transfusion. An increased volume of normal blood being aspiratedalso means that the vacuum source (e.g. syringe) will fill in a shorteramount of time, thus required more frequent replacement of the vacuumsource. Distal embolism may occur if the vacuum pressure is notsufficient, and yet the user is not aware.

An aspiration system 2 is illustrated in FIG. 43 and is configured toallow real time monitoring of catheter aspiration. The aspiration system2 comprises an aspiration catheter 4, a vacuum source 6, a valve 8,extension tubing 10, and an aspiration monitoring system 48 including anin-line pressure transducer 12. The aspiration catheter 4 has a proximalend 14 and a distal end 16 and an aspiration lumen 18 extending from theproximal end 14 to the distal end 16. The aspiration lumen 18 may besized for aspiration of thrombus, and in some embodiments may have aninner diameter of between about 0.038 cm (0.015 inches) and about 0.254cm (0.100 inches). The aspiration catheter 4 includes a hub 20 at itsproximal end which may include a female luer connector 22. Theaspiration lumen 18 at the distal end 16 of the aspiration catheter 4may include an angled orifice 24, which aids in the tracking throughtortuous or occluded vasculature. In some embodiments, a guidewire lumen26 is coupled to the distal end 16 of the aspiration catheter 4, and isconfigured to track over a guidewire 28. The vacuum source 6 maycomprise a syringe, and may be sized between 5 ml and 100 ml, or between20 ml and 60. The vacuum source 6 may comprise a VacLok® syringe, madeby Merit Medical, Salt Lake City, Utah. The vacuum source 6 may includea barrel 30 and plunger 32, with a lock 34 which is configured to retainthe plunger 32 in position in relation to the barrel 30, for example,when the plunger is pulled back in direction D to create a negativepressure (vacuum) inside the barrel 30. In some embodiments, the vacuumsource 6 may comprise any other type of evacuatable reservoir, or maycomprise a vacuum pump. The vacuum source 6 is connected to theaspiration lumen 18 of the aspiration catheter 4 via the extensiontubing 10 and the valve 8. In some embodiments, the vacuum source 6 maybe connected directly to the aspiration lumen 18 of the aspirationcatheter 4. Male luer connectors 36 and female luer connectors 38 areindicated in FIG. 43. The valve 8 may be a standard two-way stopcock, asillustrated.

The pressure transducer 12 of the aspiration monitoring system 48 isconfigured to be fluidly coupled between the vacuum source 6 and theaspiration catheter 4. In FIG. 44A, the aspiration monitoring system 48is illustrated as a self-contained device of a first embodiment. Thepressure transducer 12 comprises a housing 40 having a cavity 42extending between a first port 44 and a second port 46. In someembodiments, the first port 44 comprises a female luer and the secondport 46 comprises a male luer. In some embodiments, the first port 44comprises a female luer lock and the second port 46 comprises a maleluer lock, each of which is attachable to and detachable from acorresponding luer lock of the opposite gender. The first port 44 isconfigured to be coupled to the vacuum source 6, either directly, orwith the valve 8 and/or extension tubing 10 connected in between. Thesecond port 46 is configured to be coupled to the aspiration lumen 18 ofthe aspiration catheter 4, for example, by coupling the second port 46directly or indirectly to the hub 20 of the aspiration catheter 4. Whenthe aspiration system 2 is used to aspirate body fluids and/ormaterials, for example blood and/or thrombus, the body fluids and/ormaterials are aspirated through the aspiration lumen 18 of theaspiration catheter from the angled orifice 24 at the distal end 16 tothe female luer connector 22 at the proximal end 14, then pass throughthe second port 46 of the pressure transducer 12 first, through thecavity 42, and then through the first port 44. Depending on the amountof amount of vacuum (negative pressure) applied by the vacuum source 6,and the amount of flow resistance and resulting pressure drop along theaspiration system 2, the pressure within the cavity 42 will vary. Forexample, a more viscous fluid like blood, or a fluid having solid,semi-solid, or gel-like particles or portions, will cause more flowresistance through the relatively small aspiration lumen 18 of theaspiration catheter 4 than would water or normal saline solution. Thusthe pressure within the cavity 42 of the pressure transducer 12 willdecrease (the amount of vacuum will increase) as the flow resistance inthe aspiration lumen 18 increases.

For definition purposes, when speaking of the amount of vacuum, apressure of, for example, −15,000 pascal (−2.18 pounds per square inch,or psi) is a “larger vacuum” than −10,000 pascal (−1.45 psi).Additionally, −15,000 pascal is a “lower pressure” than −10,000 pascal.Furthermore, −15,000 pascal has a larger “absolute vacuum pressure” thandoes −10,000 pascal, because the absolute value of −15,000 is largerthan the absolute value of −10,000. In FIG. 44A, a vacuum sensor 50 isdisposed within the cavity 42 of the housing 40 and is in fluidcommunication with fluid that passes through the cavity 42. The vacuumsensor 50 may be a standard pressure sensor or transducer, including apressure sensor designed primarily for measuring positive pressure. Itmay use any type of pressure sensing technology known in the art,including MEMS Technology. In some embodiments, the vacuum sensor 50 isconfigured for highest accuracy and/or precision within the range ofpressures between about 0 pascal to about −101,325 pascal (−14.70 psi),or between about −45,000 pascal (−6.53 psi) and about −90,000 pascal(−13.05 psi), or between about −83,737 pascal (−12 psi) and about−96,527 pascal (−14 psi). In some embodiments, the power requirement forthe vacuum sensor may range from 2.5 volts DC to 10 volts DC. In someembodiments, the vacuum sensor 50 may be an analog gauge with an outputvoltage. In the self-contained embodiment of the FIG. 44A, the vacuumsensor 50 is powered by one or more battery 52. Based on the powerrequirements of the vacuum sensor 50, and the power requirements ofother components of the aspiration monitoring system 48 describedherein, in some embodiments the one or more battery 52 may range between1.5 volts and nine volts. Also contained within the housing is ameasurement device 54, which in some embodiments may comprise amicroprocessor. The measurement device 54 is coupled to the vacuumsensor 50 and receives signals from the vacuum sensor 50 indicative ofreal time measured pressure. In some embodiments, the measurement device54 includes a memory module 56 in which information is stored that maybe used by the measurement device 54, for example, in calculations.

One or more communication devices 58 a, 58 b, 58 c are included withinthe aspiration monitoring system 48 and are coupled to the measurementdevice 54. Each of the one or more communication devices 58 a-c areconfigured to generate a type of alert comprising an alert signal 60a-c, in response at least in part to activity and output of themeasurement device 54. In some embodiments, the communication device 58a may include one or more LEDs (light emitting diodes) configured togenerate a visible alert via a visible alert signal 60 a, such as lightthat is continuously illuminated, or is illuminated in a blinkingpattern. In some embodiments, lights other than LEDs may be used. Insome embodiments, the communication device 58 b may include one or morevibration generators configured to generate a tactile alert via atactile alert signal 60 b, which may include, but is not limited to,vibration or heat. In some embodiments, the vibration generator maycomprise a piezoelectric device which is configured to vibrate when avoltage is applied. In some embodiments, the communication device 58 cmay include one or more sound generating devices configured to generatean audible alert via an audible alert signal 60 c, such as a continuousnoise, or a repeating noise. In some embodiments, the sound generatingdevice may comprise a buzzer which is configured to sound one or moreaudible pitches when a voltage is applied. In some embodiments apiezoelectric device, such as that described in relation to thecommunication device 58 b may also serve as a sound generating device,included as communication device 58 c.

A user of an aspiration system 2 may desire to be notified of severalconditions which may occur during use of the aspiration system 2. Thesepotential conditions include, but are not limited to clogging, a loss ofvacuum due to filling of the vacuum source 6 and or a breach, break orpuncture in the aspiration system 2, and the engagement or aspiration ofnon-fluid, solid or semi-solid material such as thrombus. The aspirationmonitoring system 48 of FIG. 44A is configured to alert users of anaspiration system 2 about real time status of the aspiration system 2,including operational conditions, which include: whether vacuum is beingapplied or not; flow conditions, which include whether a thrombus isengaged, whether a thrombus is being actively aspirated, whether thesystem is leaking air, whether the system is clogged, whether the vacuumsource 6 is full and/or needs to be changed; or other potential set upissues. The real time feedback provided frees a user or operator fromthe need of excessive personal monitoring of the vacuum source 6,extension tubing 10, or other portions of the aspiration system 2, forimproper or undesired flow or operation conditions, and thus allows theuser to focus more attention on the patient being treated.

The pressure transducer 12 of the aspiration monitoring system 48 isconfigured to continuously measure and monitor the absolute pressureamplitude within the closed system of the aspiration system 2, and alsois configured to measure and monitor the relative pressure over time todetect noteworthy flow changes within the flow circuit of the aspirationsystem 2. Some changes are discernible via absolute pressuremeasurement, while more subtle pressure deflections may be compared to astored library in memory. Noteworthy conditions may be signaled to theuser when appropriate. In some embodiments, the unfiltered signal may beamplified by an amplifier and filtered by a filter, for example, toincrease the signal-to-noise ratio. Examples of the (background) noise57 in an unfiltered signal can be seen in FIGS. 46A-46D (labeled in FIG.46A). In some embodiments, one or more algorithms may be used, asdescribed herein, to identify particular conditions of interest.

FIG. 44B illustrates a second embodiment of an aspiration monitoringsystem 62 having a pressure transducer 12 having a vacuum sensor 50disposed within the cavity 42 of a housing 40. The vacuum sensor 50 maybe powered by at least one battery 52. In some embodiments, the pressuretransducer 12 may be reusable, and may be configured to allow chargingof the battery 52, or of a capacitor (not shown) by direct chargingmethods, or by inductive power transfer methods and devices known in theart. Unlike the aspiration monitoring system 48 of FIG. 44A, theaspiration monitoring system 62 of FIG. 44B comprises a measurementdevice 64, memory module 66, and communication device 68 which areexternal to the pressure transducer 12. A power module 72, alsoexternal, may be used to power any of the measurement device 64, memorymodule 66, or communication device 68. The communication device 68 maybe any of the communication device 58 a, 58 b, 58 c described inrelation to the aspiration monitoring system 48 of FIG. 44A, and areconfigured to product an alert via an alert signal 70. The communicationdevice 68 may be portable so that it may be positioned close to theuser.

In some embodiments, the communication device 68 may be wearable by theuser. FIG. 44C illustrates an aspiration monitoring system 78 whichincludes an antenna 80 coupled to a measurement device 76. Themeasurement device 76 is similar to the measurement device 54 of priorembodiments, except that it wirelessly sends a communication signal 84via the antenna 80 to a corresponding antenna 82 of a communicationdevice 74. In some embodiments, the communication device 74 comprises awristband which the user wears, and which may include a vibrationgenerator or heat generator. In some embodiments, the communicationdevice 74 comprises an audio speaker which may be attached to equipmentor even to the patient or user. In some embodiments, the communicationdevice 74 comprises an audio speaker on an earpiece or earbud that theuser may wear. In some embodiments, Bluetooth® communication technologymay be used.

FIG. 45A illustrates the distal end 16 of an aspiration catheter 4within a blood vessel 86 having at least one thrombus 88. The aspirationcatheter 4 is being advanced in a forward direction F, but the distalend 16 of the aspiration catheter 4 has not yet reached the proximalextremity 94 of the thrombus 88. A vacuum source 6 (FIG. 43) has beencoupled to the aspiration lumen 18 of the aspiration catheter 4 andactivated (i.e. the valve 8 is open) causing blood 96 to be aspiratedinto the aspiration lumen 18 (arrows A). Turning to FIG. 46A, acorresponding curve 98 is represented for the normal fluid (e.g. blood)vacuum over time for the condition of FIG. 45A. The curve 98 representsvacuum pressure over time sensed by the vacuum sensor 50 of any of theembodiments presented. No leaks are present and no thrombus is beingevacuated, and therefore the curve 98 includes a downward slope 99 whenthe vacuum source 6 increases the vacuum up (lowers the pressure) withinthe cavity 42 of the pressure transducer 12 to a relatively steadystate. The steady pressure curve 97 continues while blood 96 is beingaspirated. As the vacuum is decoupled from the aspiration lumen 18, forexample by closing the valve 8 or by detaching any two of the ports(e.g. luers), or if the vacuum source 6 fills completely with blood 96,then an upward slope 95 is measured.

The measurement device 54, 64 is configured to compare the curve 97 withinformation stored in the memory module 56, 66 to identify thiscondition. In some embodiments, the measurement device 54, 64 uses analgorithm to make the comparison. In some embodiments, the measurementdevice 54, 64 then sends a signal to the communication device 58 a-c,74, and the communication device 58 a-c, 74 generates an appropriatealert. Communication device 58 a, for example a particular color LED,may be illuminated, or an LED may flash in a particular pattern ornumber of flashes. Communication device 58 b may create a characteristicsound, or may generate an audio message in a number of languages. Forexample, the audio message may state, “Thrombus encountered,” or “Nothrombus encountered.” Communication device 58 c may vibrate or heat ina characteristic pattern, for example, a certain number of repetitionsor a certain frequency between repetitions. The user may determine thatan additional fluoroscopic image (e.g. angiography) or other imagingmodalities may be necessary to better identify the location of thethrombus 88.

FIG. 45B illustrates the distal end 16 of an aspiration catheter 4advanced to a position such that the distal end 16 of the aspirationcatheter 4 contacts the proximal extremity 94 of the thrombus 88. Thecorresponding curve 93 in FIG. 46B represents vacuum pressure over timesensed by the vacuum sensor 50 of any of the embodiments presented. Thecurve 93 initially has a downward slope 99 followed by a steady pressurecurve 97, as in the condition of FIG. 45A, graphed in FIG. 46A, however,when the distal end 16 of the aspiration catheter 4 contacts theproximal extremity 94 of the thrombus 88, if the aspiration causes aportion of the thrombus 88 (for example a large or relatively hardportion) to enter and become trapped in the aspiration lumen 18, then aclog condition occurs. A similar condition occurs if the distal end 16of the aspiration catheter 4 is caught on the thrombus 88 by the vacuum,with virtually nothing flowing through the aspiration lumen 18. Ineither condition, the curve 93 includes a deviation (or disturbance) influid pressure 91. If the clog (or stuck condition) continues, then aflat, depressed pressure 89 is measured.

The measurement device 54, 64 is configured to compare the curve 93 withinformation stored in the memory module 56, 66 to identify thiscondition. In some embodiments, the measurement device 54, 64 uses analgorithm to make the comparison. In some embodiments, a pre-setpressure differential ΔP1 may be stored in the memory module 56, 66 as athreshold, whereby the measurement of a pressure difference 81 less thanthis threshold does not result in the measurement device 54, 64commanding the communication device 58 a-c, 74 to send an alert signal60 a-c, 70. In some embodiments, when the pressure difference 81 isgreater than (or greater than or equal to) the pre-set pressuredifferential ΔP1, the measurement device 54, 64 then sends a signal tothe communication device 58 a-c, 74, and the communication device 58a-c, 74 generates an appropriate alert. Communication device 58 a, forexample a particular color LED, may be illuminated, or an LED may flashin a particular pattern or number of flashes. Communication device 58 bmay create a characteristic sound, or may generate an audio message in anumber of languages. For example, the audio message may state, “ClogCondition.” Communication device 58 c may vibrate or heat in acharacteristic pattern, for example, a certain number of repetitions ora certain frequency between repetitions. When the user realizes that theclog condition is present, the user may pull on the aspiration catheter4 and readvance it, in an attempt to contact a portion of the thrombus88 that can be aspirated. If a portion of the thrombus is clogged in theaspiration lumen 18, and repositioning of the aspiration catheter 4 doesnot produce good results, the aspiration catheter 4 can be removed andthe aspiration system 2 can be repurged, for example by a positivepressurization.

FIG. 45C illustrates the distal end 16 of the aspiration catheter 4 in ageneral situation during which a breach in the aspiration system 2 hasoccurred. For example, a break, leak, puncture, pinhole, loosening, ordisconnection may cause air to be pulled into the aspiration lumen 18 ofthe aspiration catheter 4, the cavity 42 of the pressure transducer 12,of the interior of the extension tubing 10, valve 8, or vacuum source 6.As graphed in the curve 85 of FIG. 46C, a downward slope 99 and asubsequent steady pressure curve 97 are measured, but at the point intime of the breach 87 an upward slope 83 begins.

The measurement device 54, 64 is configured to compare the curve 85 withinformation stored in the memory module 56, 66 to identify thiscondition. In some embodiments, the measurement device 54, 64 uses analgorithm to make the comparison. In some embodiments, the measurementdevice 54, 64 then sends a signal to the communication device 58 a-c,74, and the communication device 58 a-c, 74 generates an appropriatealert. Communication device 58 a, for example a particular color LED,may be illuminated, or an LED may flash in a particular pattern ornumber of flashes. Communication device 58 b may create a characteristicsound, or may generate an audio message in a number of languages. Forexample, the audio message may state, “System Leak.” Communicationdevice 58 c may vibrate or heat in a characteristic pattern, forexample, a certain number of repetitions or a certain frequency betweenrepetitions. Upon receiving the alert, the user will check thecomponents of the aspiration system 2 and either fix the breach orreplace one or more of the components of the aspiration system 2. Forexample, in some cases, the communication device 58 a-c, 74 may alertthe user when the measurement device 54, 64 confirms a loss of vacuum,allowing the user to change or recharge the vacuum source 6, which hasbecome depleted (e.g. by filling with blood and/or thrombus).

FIG. 45D illustrates the distal end 16 of the aspiration catheter 4during the successful aspiration of pieces or portions 90 of thethrombus 88. In some cases, the pieces or portions 90 may follow atortuous path 92, due to disturbances or collisions with the inner wallof the aspiration lumen 18 while being pulled through the aspirationlumen 18. In some cases, the pieces or portions 90 may catch and slipwithin the inner wall of the aspiration lumen 18, for example, do tovariance of the inner diameter of the aspiration lumen 18 along thelength. Either of these situations can cause a corresponding series ofincreases and decreases in the pressure being sensed by the pressuretransducer 12, while the pieces or portions 90 are traveling through theaspiration lumen 18. As graphed in the curve 79 of FIG. 46D, a downwardslope 99 and a subsequent steady pressure curve 97 are measured, but asthe pieces or portions 90 of thrombus 88 travel down the aspirationlumen 18 of the aspiration catheter 4, a deviation 77 of fluid pressurecomprising a plurality of decreases and increases in pressure (increasesand decreases in vacuum pressure) is measured. As the pieces or portions90 of thrombus 88 exit the proximal end of the aspiration lumen 18 ofthe aspiration catheter 4, a second steady pressure curve 75 ismeasured. The duration 67 of the deviation 77 is the amount of transitof the particular significant pieces or portions 90 of thrombus 88. Theduration 67 can range quite a bit, but in some cases may be less than asecond or up to about 30 seconds. When again additional pieces orportions 90 of thrombus 88 are aspirated into and travel down theaspiration lumen 18 of the aspiration catheter 4, another deviation 73of fluid pressure comprising a plurality of decreases and increases inpressure (increases and decreases in vacuum pressure) is measured. Atthe end of the curve 79, the vacuum source 6 is shown filling completelywith blood 96 and the pieces or portions 90 of thrombus 88, and so anupward slope 95 is measured.

The measurement device 54, 64 is configured to compare the curve 79 withinformation stored in the memory module 56, 66 to identify when thepieces or portions 90 of thrombus 88 are actively being aspirated, as indeviation 77 and deviation 73, and when the pieces or portions ofthrombus 88 are not being actively, or substantially, aspirated, as insteady pressure curve 97, the steady pressure curve 75, and the steadypressure curve 71. In some embodiments, the measurement device 54, 64uses an algorithm to make the comparison. In some embodiments, a pre-setpressure differential ΔP2 may be stored in the memory module 56, 66 as athreshold, whereby the measurement of a pressure difference 69 less thanthis threshold does not result in the measurement device 54, 64commanding the communication device 58 a-c, 74 to send a first type ofalert via an alert signal 60 a-c, 70. In some embodiments, when thepressure difference 69 is greater than (or greater than or equal to) thepre-set pressure differential ΔP2, the measurement device 54, 64 thensends a signal to the communication device 58 a-c, 74, and thecommunication device 58 a-c, 74 generates an appropriate alert.Communication device 58 a, for example a particular color LED, may beilluminated, or an LED may flash in a particular pattern or number offlashes. In some embodiments, the communication device 58 a may comprisea light whose intensity increases proportionally with the pressure.Communication device 58 b may create a characteristic sound, or maygenerate an audio message in a number of languages. For example, theaudio message may state, “Thrombus being aspirated.” In someembodiments, communication device 58 b may comprise one or more noisesor beeps. In some embodiments, the communication device 58 b maycomprise a particular series of beeps corresponding to each differentcondition. For example, three short beeps may correspond to no thrombusbeing aspirated, while five long, loud beeps may correspond to a systemleak. In some embodiments, a plurality of different tones (pitches) maybe used to alert a user about different conditions. As an example, a lowpitch sound may be used for a first condition (e.g. no thrombus beingaspirated) and a second, higher pitch sound may be used for a secondcondition (e.g. a system leak). In some embodiments, a plurality ofdifferent tones may be used to alert a user about a first condition anda second plurality (e.g. in a different combination, or with additionaltones) may be used to alert a user about a second condition.Communication device 58 c may vibrate or heat in a characteristicpattern, for example, a certain number of repetitions or a certainfrequency between repetitions. When the user realizes that the thrombusis being aspirated, the user may choose to advance (or retract) theaspiration catheter 4, for example with fluoroscopic visualization,along the length of the thrombus 88, in an attempt to continue theaspiration of the thrombus 88. In some cases, the user may choose tostop the advancement or retraction of the aspiration catheter 4 at acertain amount of time after the alert is generated, in order to allowthe pieces or portions 90 of thrombus 88 to completely exit theaspiration lumen 18. When the measurement device 54, 64 identifies asubsequent steady pressure curve 75, 71 that follows a deviation 77, 73,the measurement device 54, 64 in some embodiments sends a signal thatcauses the communication device 58 a-c, 74 to generate a second type ofalert via an alert signal 60 a-c, 70. For example, in some embodiments,communication device 58 b may send an audio message that states,“Thrombus no longer being aspirated.” When the user realizes that thethrombus is no longer being aspirated, the user may advance or retractthe aspiration catheter, in an attempt to contact another portion of thethrombus 88 that can be aspirated. In some embodiments, the deviation 77may be positively identified as a true deviation indicating thrombusbeing actively aspirated, pressure difference 69 is between about 700pascal and about 1700 pascal. In some embodiments, the deviation 77 maybe positively identified as a true deviation indicating thrombus beingactively aspirated, pressure difference 69 is between about 1000 pascaland about 1300 pascal. In some embodiments, the deviation 77 may bepositively identified as a true deviation indicating thrombus beingactively aspirated, pressure difference 69 is about 1138 pascal. Thepressure difference 69 may be measured by determining a baselinepressure 63 and a peak pressure 61 and determining the absolute valuedifference. For example:

Absolute value difference (AVD)=|(−89,631 pascal)−(−90,769 pascal)|=1138pascal

Or for example:

Absolute value difference (AVD)=|(−43,710 pascal)−(−45,102 pascal)|=1281pascal

The pressure difference 81 (FIG. 46B) may also represent a deviationthat may be identified in a similar manner, after which thecommunication device 58 a-c, 74 generates an appropriate alert, such as,“Clog condition.”

Because vacuum pressure is a negative pressure, the peak pressure 61, asshown in FIG. 46D, is actually a lower number than the baseline pressure63. In some embodiments, the measurement device 54, 64 may also beconfigured to make a comparison, for example by using an algorithm,between a stored differential time t1 and a duration 65 of a single oneof the plurality of decreases and increases in pressure in the deviation77. For example, in some embodiments, the deviation may be positivelyidentified as a true deviation indicating thrombus being activelyaspirated, if the duration is between about 0.001 seconds and about 0.50seconds. In some embodiments, the deviation may be positively identifiedas a true deviation indicating thrombus being actively aspirated, if theduration is between about 0.005 seconds and about 0.10 seconds. In someembodiments, the deviation may be positively identified as a truedeviation indicating thrombus being actively aspirated if the durationis between about 0.05 seconds and about 0.20 seconds. In someembodiments, the measurement device 54, 64 is configured to recognizedeviation 77 after two or more decreases and increases in pressure aremeasured. In some embodiments, the measurement device 54, 64 isconfigured to recognize deviation 77 after five or more decreases andincreases in pressure are measured. In some embodiments, the measurementdevice 54, 64 is configured to recognize deviation 77 after ten or moredecreases and increases in pressure are measured.

Insertion of the pressure transducer 12 in line in either the embodimentof FIG. 44A or the embodiment of FIG. 44B does not measurably changeperformance characteristics of the aspiration system 2, because thecavity 42 is relatively short and has a relatively large inner diameter,and thus is not a significant source of fluid flow resistance. In someembodiments, the inner diameter may be between about 2.2 mm (0.086inches) and about 3.2 mm (0.125 inches). In some embodiments, themeasurement device 54, 64, 76 need not include a microprocessor, aspre-defined set points (e.g. for certain thresholds) may be included infirmware, microcontroller, or other locations. In some embodiments,including but not limited to the embodiment of FIG. 44B, the pressuretransducer 12 may be an off-the-shelf blood pressure monitor system,which is modified or augmented with other components. In someembodiments an off-the-shelf blood pressure monitor system may be usedas the output of the aspiration monitoring system 48, 62, 78. In someembodiments, an aspiration catheter 4 may have a pressure transducer inthe distal end 16. This pressure transducer may be used as the pressuretransducer 12 of the aspiration monitoring system 48, 62, 78. In someembodiments, a pressure sensor may be located within a Tuohy-Borstvalve, and introducer sheath, a guiding catheter, or another componentof the system through which is in fluid communication with theaspiration lumen 18. In some embodiments, the pressure sensor may belocated anywhere within the aspiration lumen of the aspiration catheter.

In some embodiments, instead of an LED, the visual alert is provided bya communication device 58 a comprising a display which displays visualmessages of text in a particular language, for example, “Thrombusencountered,” “No thrombus encountered,” “Clog condition,” “Systemleak,” “Loss of vacuum,” “Thrombus being aspirated,” or “Thrombus nolonger being aspirated.” The visual messages may be combined with any ofthe other alert signals 60 a-c, 70 described herein. The aspirationmonitoring system 48, 62, 78 described herein give real time awarenessto users performing aspiration procedures, such as the removal ofthrombus via an aspiration system 2. One skilled in the art willrecognize that by knowing the real time condition of the aspirationsystem 2, the user is able to immediately make changes to the procedurein order to optimize results, increase safety for the patient and/ormedical personnel, reduce costs (e.g. number of vacuum sources 6required), and reduce procedure time (also a cost benefit). Because theuser is typically performing multiple tasks during an aspirationprocedure, the sensory aid provided by the aspiration monitoring system48, 62, 78 allows the user to focus on these tasks without having tocontinually attempt to monitor conditions which are often difficult tovisually monitor. The user may also modify and control the aspirationmonitoring system 48, 62, 78 via an input 59 (FIG. 44B), which maycomprise a data entry module, keyboard, or a series of buttons with adisplay. The input 59 may in some embodiments comprise an auditory inputwhich accepts voice commands. Alternatively, the user may inputinformation and control the aspiration monitoring system, 48, 62, 78remotely. Some of the alerts which the user may select or deselect inthe aspiration monitoring system 48, 62, 78 include, but are not limitedto: whether the aspiration system 2 is potentially blocked or clogged,or is flowing normally; whether thrombus has been contacted or not;whether a clog has occurred; whether the vacuum source 6 is adequate, orwhether it has been depleted and requires replacement; whether there isa leak in the aspiration system 2; whether setup or connection of thecomponents of the aspiration system 2 was done correctly or incorrectly;whether to advance the catheter distally; whether to retract thecatheter; whether to continue moving the catheter at the same speed;whether to increase or decrease the speed of catheter advancement;whether thrombus is actively being aspirated; and whether thrombus stopsbeing actively aspirated.

In some embodiments, alternate power sources may be used, for example,standard AC power with or without an AC/DC convertor; direct connectionto existing equipment (e.g. vacuum pumps, etc.); solar power. Theaspiration monitoring system 48, 62, 78 may be packaged sterile or maybe resterilizable by techniques known by those skilled in the art. Insome embodiments, flow or volume gauges may be used in conjunction withor instead of the pressure gauge 12, in order to determine, for example,a clog, or a change in the amount of vacuum.

Though aspiration of thrombus has been described in detail, theaspiration monitoring system 48, 62, 78 has utility in any aspirationapplication wherein heterogeneous media is being aspirated. This mayinclude the aspiration of emboli (including not thrombotic emboli) fromducts, vessels, or cavities of the body, or even from solid orsemi-solid portions of the body, including, but not limited to, portionsof fat, breasts, and cancerous tissue.

In some embodiments, the aspiration system 2 is be provided to the useras a kit with all or several of the components described, while in otherembodiments, only the aspiration monitoring system 48 is provided.Though discussion herein includes embodiments for aspiration of thrombusand blood, the definition of the word “fluid” should be understoodthroughout to comprise liquids and gases.

In some embodiments, an additional or alternate sensor may be used tomonitor flow conditions for the notification of the user, including, butnot limited to: a Doppler sensor, an infrared sensor, or a laser flowdetection device. In some embodiments, an externally-attached Dopplersensor may be employed. In some embodiments, an infrared sensor or alaser flow detection device may be employed around the extension tubing10.

Assisted Aspiration

FIG. 47 is a diagrammatic figure depicting an assisted aspiration system510. The aspiration system 510 includes a remote hand piece 512 thatcontains a fluid pump 526 and an operator control interface 506. In onecontemplated embodiment, the system 510 is a single use disposable unit.The aspiration system 510 may also include extension tubing 514, whichcontains a fluid irrigation lumen 502 and an aspiration lumen 504, andwhich allows independent manipulation of a catheter 516 withoutrequiring repositioning of the hand piece 512 during a procedureperformed with the aspiration system 510. Extension tubing 514 may alsoact as a pressure accumulator. High pressure fluid flow from the pump526, which may comprise a displacement pump, pulses with each stroke ofthe pump 526 creating a sinusoidal pressure map with distinct variationsbetween the peaks and valleys of each sine wave. Extension tubing 514may be matched to the pump 526 to expand and contract in unison witheach pump pulse to reduce the variation in pressure caused by the pumppulses to produce a smooth or smoother fluid flow at tip of catheter516. Any tubing having suitable compliance characteristics may be used.The extension tubing 514 may be permanently attached to the pump 526 orit may be attached to the pump 526 by a connector 544. The connector 544is preferably configured to ensure that the extension tubing 514 cannotbe attached to the pump 526 incorrectly.

An interface connector 518 joins the extension tubing 514 and thecatheter 516 together. In one contemplated embodiment, the interfaceconnector 518 may contain a filter assembly 508 between high pressurefluid injection lumen 502 of the extension tubing 514 and a highpressure injection lumen 536 of the catheter 516 (FIG. 49). The catheter516 and the extension tubing 514 may be permanently joined by theinterface connector 518. Alternatively, the interface connector 518 maycontain a standardized connection so that a selected catheter 516 may beattached to the extension tubing 514. In some embodiments, the filterassembly 508 may be removably coupled to the extension tubing 514 by aquick disconnect connection.

Attached to the hand piece 512 are a fluid source 520 and a vacuumsource 522. A standard hospital saline bag may be used as fluid source520; such bags are readily available to the physician and provide thenecessary volume to perform the procedure. Vacuum bottles may providethe vacuum source 522 or the vacuum source 522 may be provided by asyringe, a vacuum pump or other suitable vacuum source. The filterassembly 508 serves to filter particulate from the fluid source 520 toavoid clogging of the high pressure injection lumen 536 and an orifice542 (FIG. 49). As described herein, distal sections of the high pressureinjection lumen 536 may be configured with small inner diameters, and tothe filter assembly 508 serves to protect their continuing function. Byincorporating one of a variety of catheters 516 into the assistedaspiration system 510, for example with varying lumen configurations(inner diameter, length, etc.), a variety of aspiration qualities(aspiration rate, jet velocity, jet pressure) may be applied in one ormore patients. These aspiration qualities can be further achieved byadjustment of the pump 526, to modify pump characteristics (flow rate,pump pressure). In some embodiments, the catheter 516 may be usedmanually, for example, without the pump 526, and controlled by handinjection. The manual use of the catheter 516 may be appropriate forcertain patient conditions, and may serve to reduce the cost of theprocedure.

In one contemplated embodiment, the catheter 516 has a variablestiffness ranging from stiffer at the proximal end to more flexible atthe distal end. The variation in the stiffness of the catheter 516 maybe achieved with a single tube with no radial bonds between two adjacenttubing pieces. For example, the shaft of the catheter 516 may be madefrom a single length of metal tube that has a spiral cut down the lengthof the tube to provide shaft flexibility. Variable stiffness may becreated by varying the pitch of the spiral cut through different lengthsof the metal tube. For example, the pitch of the spiral cut may begreater (where the turns of the spiral cut are closer together) at thedistal end of the device to provide greater flexibility. Conversely, thepitch of the spiral cut at the proximal end may be lower (where theturns of the spiral cut are further apart) to provide increasedstiffness. A single jacket covers the length of the metal tube toprovide for a vacuum tight catheter shaft. Other features of catheter516 are described with reference to FIG. 49, below.

FIG. 48 is a diagrammatic view showing more detail of the hand piece 512and the proximal portion of assisted catheter aspiration system 510. Thehand piece 512 includes a control box 524 where the power and controlsystems are disposed. The pump 526 may be a motor driven displacementpump that has a constant output. This pump displacement to cathetervolume, along with the location of the orifice 542 (exit) of thecatheter high pressure lumen 536 within the aspiration lumen 538 (FIG.49), ensures that no energy is transferred to the patient from thesaline pump as all pressurized fluid is evacuated by the aspirationlumen. A prime button 528 is mechanically connected to a prime valve530. When preparing the device for use, it is advantageous to evacuateall air from the pressurized fluid system to reduce the possibility ofair embolization. By depressing the prime button 528, the user connectsthe fluid source 520 to the vacuum source 522 via the pump 526. Thisforcefully pulls fluid (for example 0.9% NaCl solution, or “saline”, no“normal saline”, or heparinized saline) through the entire pump system,removing all air and positively priming the system for safe operation. Apressure/vacuum valve 532 is used to turn the vacuum on and offsynchronously with the fluid pressure system. One contemplated valve 532is a ported one way valve. Such a valve is advantageous with respect tomanual or electronic valve systems because it acts as a tamper proofsafety feature by mechanically and automatically combining theoperations of the two primary systems. By having pressure/vacuum valve532, the possibility of turning the vacuum on without activating thefluid system is eliminated.

The operator control interface 506 is powered by a power system 548(such as a battery or an electrical line), and may comprise anelectronic control board 550, which may be operated by a user by use ofone or more switches 552 and one or more indicator lamps 554. Thecontrol board 550 also monitors and controls several device safetyfunctions, which include over pressure and air bubble detection andvacuum charge. A pressure sensor 564 monitors pressure, and senses thepresence of air bubbles. Alternatively, an optical device 566 may beused to sense air bubbles. In one contemplated embodiment, the pumppressure is proportional to the electric current needed to produce thatpressure. Consequently, if the electric current required by pump 526exceeds a preset limit, the control board will disable the pump bycutting power to it. Air bubble detection may also be monitored bymonitoring the electrical current required to drive the pump at anyparticular moment. In order for a displacement pump 526 to reach highfluid pressures, there should be little or no air (which is highlycompressible) present in the pump 526 or connecting system (includingthe catheter 516 and the extension tubing 514). The fluid volume issmall enough that any air in the system will result in no pressure beinggenerated at the pump head. The control board monitors the pump currentfor any abrupt downward change that may indicate that air has enteredthe system. If the rate of drop is faster than a preset limit, thecontrol board will disable the pump by cutting power to it until theproblem is corrected. Likewise, a block in the high pressure lumen 536,which may be due to the entry of organized or fibrous thrombus, or asolid embolus, may be detected by monitoring the electrical currentrunning the pump 526. In normal use, the current fluxuations of the pump526 are relatively high. For example, the pump may be configured so thatthere is a variation of 200 milliAmps or greater in the current duringnormal operation, so that when current fluxuations drop below 200milliAmps, air is identified, and the system shuts down. Alternatively,current fluxuations in the range of, for example, 50 milliAmps to 75milliAmps may be used to identify that air is in the system.Additionally, an increase in the current or current fluxuations mayindicate the presence of clot or thrombus within the high pressure lumen536. For example, a current of greater than 600 milliAmps may indicatethat thrombus it partially or completely blocking the high pressurelumen 536, or even the aspiration lumen 538.

A vacuum line 556, connected to the vacuum source 522, may be connectedto a negative pressure sensor 558. If the vacuum of the vacuum source522 is low or if a leak is detected in the vacuum line 556, the controlboard 550 disables the pump 526 until the problem is corrected. Thenegative pressure sensor 558 may also be part of a safety circuit 560that will not allow the pump 526 to run if a vacuum is not present.Thereby a comprehensive safety system 562, including the safety circuit560, the pressure sensor 564 and/or the optical device 566, and thenegative pressure sensor 558, requires both pump pressure and vacuumpressure for the system to run. If a problem exists (for example, ifthere is either a unacceptably low pump pressure or an absence ofsignificant vacuum), the control board 550 will not allow the user tooperate the aspiration system 510 until all problems are corrected. Thiswill keep air from being injected into a patient, and will assure thatthe aspiration system 510 is not operated at incorrect parameters.

FIG. 49 is a diagrammatic view of the distal end portion 568 of theassisted catheter aspiration system 510, showing more details of thecatheter 516. The catheter 516 is a single-operator exchange catheterand includes a short guidewire lumen 534 attached to the distal end ofthe device. The guidewire lumen 534 can be between about 1 and about 30cm in length, or between about 5 and about 25 cm in length, or betweenabout 5 and about 20 cm in length, or approximately 13.5 cm in length.An aspiration lumen 538 includes a distal opening 540 which allows avacuum (for example, from vacuum source 522) to draw thrombotic materialinto the aspiration lumen 538. A high pressure lumen 536 includes adistal orifice 542 that is set proximally of distal opening 540 by a setamount. For example, distal orifice 42 can be set proximally of distalopening 540 by about 0.0508 cm (0.020 inches), or by 0.0508 cm±0.00762cm (0.020 inches±0.003 inches) or by another desired amount. The orifice542 is configured to spray across the aspiration lumen to macerateand/or dilute the thrombotic material for transport to vacuum source522, for example, by lowering the effective viscosity of the thromboticmaterial. The axial placement of the fluid orifice 542 is such that thespray pattern interaction with the opposing lumen wall preferablyproduces a spray mist and not a swirl pattern that could force embolicmaterial out from the distal opening 540. The system may be configuredso that the irrigation fluid leaves the pump at a pressure of betweenabout 3,447,378 pascal (500 psi) and about 10,342,135 pascal (1500 psi).In some embodiments, after a pressure head loss along the high pressurelumen 536, the irrigation fluid leaves orifice 542 at between about4,136,854 pascal (600 psi) and about 8,273,708 pascal (1200 psi), orbetween about 4,481,592 pascal (650 psi) and about 5,860,543 pascal (850psi). In some cases, it may be possible (and even desired) to use theassisted catheter aspiration system 510 without operating the pump 526,and thus use the catheter 516 while providing, for example, a handsaline injection via a syringe.

When normal blood flow is achieved after unblocking occlusions orblockages from atherosclerotic lesions and/or thrombosis, there issometimes a risk of reperfusion injury. This may be particularlysignificant following thrombectomy of vessels feeding the brain fortreatment of thromboembolic stroke, or following thrombectomy ofcoronary vessels feeding the myocardium. In the case of therevascularization of myocardium following a coronary intervention (e.g.thrombectomy). Reperfusion injury and microvascular dysfunction may bemechanisms that limit significant or full recovery of revascularizedmyocardium. The sudden reperfusion of a section of myocardium that hadpreviously been underperfused may trigger a range of physiologicalprocesses that stun or damage the myocardium. Distal coronary emboli,such as small portions of thrombus, platelets and atheroma, may alsoplay a part. Controlled preconditioning of the myocardium at risk hasbeen proposed to limit the effect of reperfusion injury andmicrovascular dysfunction. The embodiments of the thrombectomy systems100, 300 presented herein may be combined with additional features aimedat allowing flow control, in order to limit the potential dangers due toreperfusion following thrombectomy.

FIGS. 50A and 50B illustrate a thrombectomy system 600 comprising acatheter 606 and a guiding catheter 608. The catheter 606 may be anaspiration or thrombectomy catheter as previously described, and may ormay not comprise a proximal sealing member. Alternatively, the catheter606 may be used for partial or complete occlusion of the blood vesseldistal of the guiding catheter 608. One purpose for this use is for flowcontrol, as described above, wherein the distal tube 614 or anotherportion of the catheter 606 may be expanded to partially or completelyocclude a blood vessel for a period of time. The catheter 606 may be acombination of an aspiration catheter and a catheter for flow control orocclusion. For example, the distal end of the distal tube 614 mayprovide some flow control in relation to the blood vessel wall, and theproximal end of the distal tube 614 may provide engagement with theguiding catheter. The guiding catheter 608 may, for example, have anouter diameter of 6 French, an inner lumen diameter of approximately0.183 cm (0.072 inches), and have a total length of approximately 100cm. The catheter 606 is configured to be placed through the inner lumenof the guiding catheter 608. The guiding catheter 608 may comprise acomposite extruded and braided tubular structure, which has sufficientflexibility and pushability to reach a target area. The guiding catheter608 may also have a pre-shaped tip. For example the tip shape may aid incannulating coronary arteries. The catheter 606 comprises a distal tube614 which is configured to be extendable out of the inner lumen of theguiding catheter 608, such that a distal end 616 of the distal tube 614can be advanced a desired length into the blood vessel so that it can beplaced adjacent the target area. The proximal end 618 of the distal tube614 is configured to remain within the inner lumen of the guidingcatheter 608, for example, at a region near the distal end of theguiding catheter 608. In some embodiments, the catheter 606 includes aradiopaque marker, which may comprise a band secured to the thrombectomycatheter, and made from radiodense material, such as platinum, gold, orother similar materials. In some embodiments, the distal tube 614 may beformed of polymeric materials containing radiopaque material, such astitanium dioxide (TiO₂).

The distal tube 614 comprises a tubular braided member whose diameterincreases as the distal tube is made shorter (the distal end 616 andproximal end 618 are brought toward one another) and whose diameterdecreases as the distal tube is made longer (the distal end 616 andproximal end 618 are moved away from one another). A tubular member ofthis type is sometimes referred to as a “Chinese finger trap.” Astretchable material (such as silicone or urethane) may be used in someembodiments to fill in the spaces between the woven filaments in orderto make a water-tight wall. As in certain other embodiments presentedherein, a support member 626 is attached to the proximal end 618 of thedistal tube 614 and is used to track the catheter 606 through theguiding catheter 608 and through the vasculature. A push/pull member 605is attached to the distal end 616 of the distal tube 614 and, like thesupport member 626, extends proximally, and out of the proximal end ofthe guiding catheter 608 for access by a user. The support member 626and the push/pull member 605 each have sufficient tensile strength andsufficient column strength such that each can be pushed and/or pulledaccordingly, to cause the distal tube 614 to shorten or lengthen inlength, thus changing its diameter. The support member 626 and thepush/pull member 605 are each also lockable in relation to each other attheir proximal ends, for example, just proximal to the proximal end ofthe guiding catheter, such that they are no longer able tolongitudinally move independent of each other. This locks the distaltube 614 in its particular condition (diameter and length). The catheter606 may be manipulated by the user so that support member 626 is pulledwhile the push/pull member 605 is pushed, thus elongating the distaltube 614 while decreasing its diameter (FIG. 50B). In thisconfiguration, the distal tube 614 can be easily inserted through theguiding catheter 608. Once in a desired location within the vasculature,the catheter 606 may be manipulated by the user so that support member626 is pushed while the push/pull member 605 is pulled, thus shorteningthe distal tube 614 while increasing its diameter (FIG. 50A). If this isdone while the proximal end 618 of the distal tube 614 is within thedistal tip of the inner lumen of the guiding catheter 608, an extendedlumen may be made, which includes the lumen of the distal tube 614 andthe inner lumen of the guiding catheter 608. If the proximal end 618 ofthe distal tube 614 has a ring of fill or coating material around itsouter surface, for example, a stretchable material such as silicone orurethane, a seal may be created between the outer diameter of the distaltube 614 and the inner diameter of the guiding catheter 608. This isappropriate for an aspiration catheter mode. If flow control is desired,the distal tube 614 may be shortened and expanded in the same manner tothat it engages the wall of the blood vessel at a desired location. Insome embodiments, the push/pull member 605 and/or the support member 626are constructed from hypo tubing, including but not limited to stainlesssteel hypo tubing or nitinol hypo tubing.

FIGS. 51A-51 c show how the size of the distal tube 614 may bemanipulated to reach different specific diameters.Longitudinally-displaced markings 677 a, 677 b, 677 c, 679 or detents onthe proximal ends 649, 651 of the support member 626 and/or thepush/pull member 605, respectively, may indicate particularcorresponding sizes (diameters or lengths) of the distal tube 614. Forexample, in FIG. 51A, an approximately 5 French diameter configurationof the distal tube 614 may be used for delivering it through the guidingcatheter 608. In FIG. 51B, an approximately 6 French diameterconfiguration of the distal tube 614 may be used when it is trackedthrough the vasculature, for example, near a lesion site or target site.In FIG. 51C, an approximately 7 French diameter configuration of thedistal tube 614 may be used when it is expanded towards or against thewall of a blood vessel. One or more loops 675 are configured to maintainthe distance between the support member 626 and the push/pull member 605in the radial direction (in relation to the distal tube 614). In someembodiments, the one or more loops 675 may be located near the proximalend 618 of the distal tube 614. FIGS. 51A-51C also show how in someembodiments, the push/pull member 605 may be constructed of flat wire.The support member 626 may also be constructed of flat wire.

FIG. 52 shows an additional sleeve 607 which may be placed over thedistal tube 614 to further constrain its diameter for delivery throughthe guiding catheter 608 and/or the vasculature. The sleeve 607 mayextend proximally and out the proximal end of the guiding cateteter 608so that it can be pulled off in a proximal direction to allow the distalsleeve 614 to expand. The sleeve 607 may be used in addition to thepush/pull member 605, or may be used in lieu of the push/pull member 605and its utility in relation to the support member 626. In an alternativeembodiment seen in FIG. 54, the sleeve 607 may comprise an elongatedistal tube 617 which is coupled to a proximal wire or pusher member619, this allowing a user to handle both the proximal wire 619 of thesleeve 607 and the support member 626 of the catheter 606 while removingthe sleeve 607 from the patient. This would aid in holding the distaltube 614 at its desired location in the vasculature (and/or in theguiding catheter 608) while removing the sleeve 607. A portion 621 ofthe distal tube 614 which may remain distal of the sleeve 607 maycomprise a non-expandable section.

FIG. 53 illustrates a thrombectomy catheter which may share certainelements of the embodiments of FIGS. 29-42. In this particularembodiment, a high pressure saline injection lumen 609 comprises two ormore sections. As depicted, the injection lumen 609 includes a proximalportion 685, a middle portion 683 and a distal portion 681. The middleportion 683 is configured to telescope within the proximal portion 685and the distal portion 681 is configured to telescope within the middleportion 683. Each portion may be constructed from precision tubing orhypo tubing, such as polyimide or nitinol, such that the difference indiameter between the opposing outer diameter and inner diameter of twoneighboring tubes is very small, in order to create a capillary sealbetween the two. For example, in some embodiments the difference indiameters may be about 0.002 cm (0.0008 inches) or less, or in someembodiments about 0.001 cm (0.0004 inches) or less, or in someembodiments about 0.0005 cm (0.0002 inches) or less. This allows asection of injection lumen 609 that has a variable length, while beingdynamically sealed, thus minimizing or eliminating any leakage attelescope points 611, 613, and allowing all or the vast majority of theinjected saline to exit at exit port 615. In some embodiments, thecapillary seal should be liquid tight, or water tight (saline tight),and in some embodiments need not be air tight (gas tight). Aprogressively smaller inner diameter from the proximal portion 685 tothe distal portion 681 helps to maintain a high pressure jet at the exitport 615 (maximum pressure), without requiring too large of a pump headpressure. During delivery (tracking) of the catheter, a stylet may beplaced within the injection lumen 609 in order to add stiffness, improvetransition flexibility and protect the telescope points 611, 613 fromdamage. The stylet may be removed once the catheter is tracked to itsdesired location, and prior to the injection of saline and theaspiration of thrombus. In some embodiments, the proximal portion 685may have an outer diameter of between about 0.0508 cm (0.020 inches) and0.0732 cm (0.030 inches) or about 0.066 cm (0.026 inches). In someembodiments, the middle portion 683 may have an outer diameter ofbetween about 0.0305 cm (0.012 inches) and 0.0559 cm (0.022 inches) orabout 0.0406 cm (0.016 inches). In some embodiments, the distal portion681 may have an outer diameter of between about 0.020 cm (0.008 inches)and 0.0406 cm (0.016 inches) or about 0.0305 cm (0.012 inches). In someembodiments, the proximal portion 685 may have an inner diameter ofabout 0.559 cm (0.022 inches), the middle portion 683 may have an innerdiameter of about 0.0483 cm (0.019 inches), and the distal portion 681may have an inner diameter of about 0.028 cm (0.011 inches). In thedistal portion 681, an inner diameter of between about 0.0229 cm (0.009inches) and about 0.0381 cm (0.015 inches) optimizes the deliveryvolume, while minimizing the outer diameter of the distal portion 681,thus maintaining the largest possible aspiration lumen cross-sectionalarea. In some embodiments, the distal tube 614 is a Chinese finger trap(braided tubular member) as previously described, and thus, thetelescoping of the injection lumen 609 tubes allows the length change ofthe distal tube 614 freely. In this embodiment or any of the embodimentsherein, the distal tube 614 may comprise a bumper of softer material atthe distal end to add atraumatic characteristics. In alternativeembodiments which do not require the telescoping of the injection lumen609, the multiple layers of different diameter tubes may still be usedin order to create a transition from larger diameter to smaller diameterand from stiffer to more flexible moving from the proximal end to thedistal end. The tube sections may in this case be adhesively, epoxy orheat bonded together, or may be friction fit. FIG. 59 illustratespossible dimensions and assembly of an embodiment. The proximal portion687 may comprise 0.066 cm×0.048 cm (0.026 inches×0.019 inches) stainlesssteel hypo tubing, for example, 304 series stainless steel. The middleportion 689 may comprise 0.066 cm×0.048 cm (0.016 inches×0.013 inches)nitinol tubing. The distal portion 691 may comprise polymeric tubinghaving a proximal outer diameter of about 0.028 cm (0.011 inches)tapering down distally to an outer diameter of about 0.028 cm (0.011inches). A radiopaque marker band 693 may be carried on the distalportion having the 0.028 cm (0.011 inches) outer diameter. In someembodiments the high pressure injection lumen 609 may be secured to theinner wall of the distal tube 614, so that it will not severely flex orkink, and thus interfere with passage of a guidewire 28, 134 or cause apinch or clog in the high pressure injection lumen 609. The highpressure injection lumen 609 may be secured with adhesive or otherequivalent techniques.

FIG. 55 illustrates the proximal end 618 of an embodiment of the distaltube 614 of the catheter 606 having an expanding structure 695 whichseals against the inner diameter 643 of the guiding catheter 608. Thismay seal via the size of its formed diameter or it may be expandable bythe user, for example, by using the combination of the support member626 and the push/pull member 605 described herein.

FIGS. 56A-56C illustrate the flow control mode of the catheter 606 forapproaching and/or sealing against the blood vessel wall. In someembodiments, the distal tube 614 may include a portion that has adiameter that is less than the blood vessel diameter. In theseembodiments, the push/pull member 605 may be pulled and the supportmember 626 pushed in order to deliver the distal tube 614 against thevessel wall (while the diameter is increased and the length isshortened). In other embodiments, the distal tube 614 may include aportion that has a diameter that is about the same or larger than theblood vessel diameter. In these embodiments, the push/pull member 605may be pushed and the support member 626 pulled in order to decrease thediameter (while increasing the length) to allow delivery down theguiding catheter 608 and through the vasculature. FIG. 56B illustratesthe distal tube 614 extending from the guiding catheter 608, andexpanded to seal against the wall of the blood vessel 102. FIG. 56Cillustrates the distal tube 614 in a reduced diameter state configuredfor placement through the inner lumen 699 of the guiding catheter 608.

FIG. 57 illustrates an embodiment of the distal tube 614 with theChinese finger trap in which pulling on the push/pull member 605 causesthe distal tube 614 to invert at an inversion point 697. In someembodiments, the inversion may be done partially and may be used tocause an increase in the diameter of the distal tube 614 (for example,to perform flow control in the blood vessel). In some embodiments, theinversion may be done to remove the distal tube 614 from the vasculatureand into the guiding catheter 608 or to remove the distal tube from theguiding catheter 608. By pushing on the push/pull member 605, the distaltube 614 may be delivered into a location in the blood vessel.

FIGS. 58A-58B illustrate how both flow control and the coupling to theguiding catheter 608 may be achieved using two different catheters,labeled in FIG. 58 as first catheter 661 and second catheter 663. Thesecond catheter 663 (having support member 665) and the first catheter661 (having support member 667) may each be delivered together within alarger delivery catheter 669 (having support member 671). After deliverythrough the guiding catheter 608 and to or near a target site (forexample a clot/thrombus and/or an atherosclerotic lesion), the deliverycatheter 669 is removed by pulling it proximally, and the first catheter661 is positioned in the blood vessel 102 for flow control, and/oradjacent a thrombus 104, and the second catheter 663 is positioned in acoupling manner to the guiding catheter 608.

FIG. 60 an embodiment for a catheter 700 which also makes use of adistal tube using the Chinese finger trap braided tubular member 714. Inthis embodiment, a wire 702, for example a Nitinol wire, istelescopically located within a proximal 704. In some embodiments, alength of a more flexible material 706, such as polyimide is attacheddistal of the wire 702 for a transition of flexibility. The proximal end718 of the distal tube 714 has a seal section 724 for engaging with theguiding catheter 608. The proximal end of the wire 702 extendsproximally of the proximal end of the proximal tube 704. By pushing onthe proximal tube 704 and pulling on the wire 702 at each of theirrespective proximal ends, a user may expand the distal tube 714 for flowcontrol (e.g. blocking or slowing down blood flow that is coming fromthe right side of FIG. 60 to the left side of FIG. 60). A thrombectomyprocedure may be performed through the extended lumen comprising thelumen of the distal tube and the inner lumen of the guiding catheter.Any combination of the embodiments disclosed herein may be used tocreate a combination flow control and thrombectomy embodiment. Thethrombectomy portion may include aspiration only, or may combineaspiration and saline injection.

In one embodiment, an aspiration system includes an elongate tubularmember for insertion into the vasculature of a patient, the elongatetubular member having a proximal end, a distal end, and a lumenextending from the proximal end to the distal end, the lumen having afirst diameter adjacent the distal end, an aspiration catheter having aproximal end and a distal end and configured to be inserted through thelumen of the elongate tubular member, the aspiration catheter includinga tubular aspiration member having a proximal end and a distal end andconfigured to at least partially extend out of the lumen of the elongatetubular member at the distal end of the elongate tubular member and intothe vasculature of the patient, an elongate support member coupled tothe tubular aspiration member and extending between the proximal end ofthe aspiration catheter and the proximal end of the tubular aspirationmember, a plurality of annular seals linearly arrayed on an outersurface of the tubular aspiration member, each of the plurality ofannular seals having an outer diameter which is greater than the firstdiameter of the lumen of the elongate tubular member, wherein theplurality of annular seals includes a first seal located adjacent theproximal end of the tubular aspiration member and a second seal locateda distance d distally of the first seal on the tubular aspirationmember, and wherein the distal end of the tubular aspiration memberextends a length L from the distal end of the elongate tubular memberwhen the first seal is engaged with the first diameter at the distal endof the elongate tubular member and the distal end of the tubularaspiration member extends a length L−d from the distal end of theelongate tubular member when the second seal is engaged with the firstdiameter at the distal end of the elongate tubular member, and a vacuumsource configured for coupling to the proximal end of the elongatetubular member such that liquid having a viscosity of about 0.0025pascal-seconds (2.5 cP) adjacent the distal end of the tubularaspiration member is aspirated into the distal end of the tubularaspiration member and through the elongate tubular member when eitherthe first seal or the second seal is engaged with the first diameter atthe distal end of the elongate tubular member.

In another embodiment, an aspiration system includes an elongate tubularmember for insertion into the vasculature of a patient, the elongatetubular member having a proximal end, a distal end, and a lumenextending from the proximal end to the distal end, an aspirationcatheter having a proximal end and a distal end and configured to beinserted through the lumen of the elongate tubular member, theaspiration catheter having a tubular aspiration member having a proximalend and a distal end and configured to at least partially extend out ofthe lumen of the elongate tubular member at the distal end of theelongate tubular member and into the vasculature of the patient, anelongate support member coupled to the tubular aspiration member andextending between the proximal end of the aspiration catheter and theproximal end of the tubular aspiration member, an annular sealing memberhaving a first end, a second end and a wall, the first end coupled tothe tubular aspiration member and having a first diameter and the secondend having a second diameter greater than the first diameter, the secondend located distally from the first end, a vacuum source configured forcoupling to the proximal end of the elongate tubular member, and whereinthe distal end of the annular sealing member creates a seal against thelumen of the elongate tubular member, substantially preventing liquidhaving a viscosity of about 0.0025 pascal-seconds (2.5 cP) from passingthrough space between the elongate tubular member and the tubularaspiration member in a distal to proximal direction when the vacuumsource is applied to the proximal end of the elongate tubular member.

In another embodiment, an aspiration system includes an elongate tubularmember for insertion into the vasculature of a patient, the elongatetubular member having a proximal end, a distal end, and a lumenextending from the proximal end to the distal end, the lumen having afirst diameter adjacent the distal end, an aspiration catheter having aproximal end and a distal end and configured to be inserted through thelumen of the elongate tubular member, the aspiration catheter includinga tubular aspiration member having a proximal end and a distal end andconfigured to at least partially extend out of the lumen of the elongatetubular member at the distal end of the elongate tubular member and intothe vasculature of the patient, an elongate support member coupled tothe tubular aspiration member and extending between the proximal end ofthe aspiration catheter and the proximal end of the tubular aspirationmember, a hydrogel seal disposed on at least a cylindrical outer surfaceportion of the tubular aspiration member and having a non-hydrateddiameter and an unconstrained hydrated diameter, the non-hydrateddiameter less than the first diameter of the elongate tubular member andthe unconstrained hydrated diameter greater than the first diameter ofthe elongate tubular member, such that the hydrogel seal is configuredto seal against the first diameter of the elongate tubular member whenit is hydrated, and a vacuum source configured for coupling to theproximal end of the elongate tubular member such that liquid having aviscosity of about 0.0025 pascal-seconds (2.5 cP) adjacent the distalend of the tubular aspiration member is aspirated into the distal end ofthe tubular aspiration member and through the elongate tubular memberwhen the hydrogel seal is engaged with the first diameter at the distalend of the elongate tubular member.

In another embodiment, an aspiration system includes an elongate tubularmember for insertion into the vasculature of a patient, the elongatetubular member having a proximal end, a distal end, and a lumenextending from the proximal end to the distal end, an aspirationcatheter having a proximal end and a distal end and configured to beinserted through the lumen of the elongate tubular member, theaspiration catheter including a tubular aspiration member having aproximal end and a distal end and configured to at least partiallyextend out of the lumen of the elongate tubular member at the distal endof the elongate tubular member and into the vasculature of the patient,and a vacuum source configured for coupling to the proximal end of theelongate tubular member such that when the distal end of the tubularaspiration member is extended out of the distal end of the elongatetubular member at least 5 cm, liquid having a viscosity of about 0.0025pascal-seconds (2.5 cP) adjacent the distal end of the tubularaspiration member is aspirated into the distal end of the tubularaspiration member and through the elongate tubular member at the sametime that liquid having a viscosity of about 0.0025 pascal-seconds (2.5cP) adjacent the distal end of the elongate tubular member is aspiratedinto space between the elongate tubular member and the tubularaspiration member and through the elongate tubular member. In someembodiments, the aspiration system is configured such that the proximalend of the tubular aspiration member is configured to extend proximallyfrom the proximal end of the elongate tubular member when the distal endof the tubular aspiration member extends into the vasculature of thepatient. In some embodiments, the aspiration system is configured suchthat the proximal end of the tubular aspiration member is configuredreside within the elongate tubular member when the distal end of thetubular aspiration member extends into the vasculature of the patient.In some embodiments, the aspiration system further includes an elongatesupport member coupled to the tubular aspiration member and extendingbetween the proximal end of the aspiration catheter and the proximal endof the tubular aspiration member.

In another embodiment, an aspiration system includes an elongate tubularmember for insertion into the vasculature of a patient, the elongatetubular member having a proximal end, a distal end, and a lumenextending from the proximal end to the distal end, the lumen having afirst diameter adjacent the distal end, an aspiration catheter having aproximal end and a distal end and configured to be inserted through thelumen of the elongate tubular member, the aspiration catheter includinga tubular aspiration member having a proximal end, a distal end, aninner diameter and an outer diameter and configured to at leastpartially extend out of the lumen of the elongate tubular member at thedistal end of the elongate tubular member and into the vasculature ofthe patient, an elongate support member coupled to the tubularaspiration member and extending between the proximal end of theaspiration catheter and the proximal end of the tubular aspirationmember, the elongate support member having a distal end including apartial cylinder having an outer radius and an inner radius, one of theouter radius and inner radius configured to substantially match one ofthe outer diameter and inner diameter of the tubular aspiration memberfor joining thereto, a seal disposed on the tubular aspiration memberconfigured to seal against the first diameter of the elongate tubularmember, and a vacuum source configured for coupling to the proximal endof the elongate tubular member such that liquid having a viscosity ofabout 0.0025 pascal-seconds (2.5 cP) adjacent the distal end of thetubular aspiration member is aspirated into the distal end of thetubular aspiration member and through the elongate tubular member whenthe seal is engaged with the first diameter at the distal end of theelongate tubular member.

In another embodiment, a forced aspiration system includes an elongatetubular member for insertion into the vasculature of a patient, theelongate tubular member having a proximal end, a distal end, and a lumenextending from the proximal end to the distal end, the lumen having afirst diameter adjacent the distal end, a forced aspiration catheterhaving a proximal end and a distal end and configured to be insertedthrough the lumen of the elongate tubular member, the forced aspirationcatheter including, a tubular aspiration member having a proximal end, adistal end, an inner lumen, and an outer diameter and configured to atleast partially extend out of the lumen of the elongate tubular memberat the distal end of the elongate tubular member and into thevasculature of the patient, an elongate tubular support member coupledto the tubular aspiration member and having a lumen extending betweenthe proximal end of the aspiration catheter and the proximal end of thetubular aspiration member, at least one orifice located adjacent thedistal end of the tubular aspiration member, the at least one orificeconfigured to allow high pressure liquid injected through the lumen ofthe elongate tubular support member to be released into the inner lumenof the tubular aspiration member, and a seal disposed on the tubularaspiration member configured to seal against the first diameter of theelongate tubular member, a vacuum source configured for coupling to theproximal end of the elongate tubular member, and a pressurized liquidsource configured for coupling to the proximal end of the lumen of theelongate tubular support member. In some embodiments, the forcedaspiration system is configured such that the seal sealingly engageswith the first diameter of the elongate tubular member when an internalpressure of the elongate tubular member immediately proximal to andadjacent the seal is increased upon coupling the elongate tubularsupport member to the pressurized liquid source.

In another embodiment, a method for aspirating material from a patientincludes providing an elongate tubular member having a proximal end, adistal end, and a lumen extending from the proximal end to the distalend, the lumen having a first diameter adjacent the distal end,providing an aspiration catheter having a proximal end and a distal endand configured to be inserted through the lumen of the elongate tubularmember, the aspiration catheter including a tubular aspiration memberhaving a proximal end and a distal end and configured to at leastpartially extend out of the lumen of the elongate tubular member at thedistal end of the elongate tubular member and into the vasculature ofthe patient, an elongate support member coupled to the tubularaspiration member and extending between the proximal end of theaspiration catheter and the proximal end of the tubular aspirationmember, and an annular sealing member coupled to the tubular aspirationmember and having a first diameter configured to seal against the firstdiameter of the elongate tubular member, placing the elongate tubularmember into the vasculature of the patient, placing the aspirationcatheter through the elongate tubular member so that the distal end ofthe tubular aspiration member extends from the distal end of theelongate tubular member and is adjacent a target area and the annularsealing member is aligned with the first diameter of the elongatetubular member, and coupling a vacuum source to the proximal end of theelongate tubular member so that material adjacent the target area isaspirated through the tubular aspiration member and the elongate tubularmember.

In another embodiment, a method for treating patients includes providinga first elongate tubular member having a proximal end, a distal end, anda lumen extending from the proximal end to the distal end, the lumenhaving a first diameter adjacent the distal end, providing a firstaspiration catheter having a proximal end and a distal end andconfigured to be inserted through the lumen of the first elongatetubular member, the first aspiration catheter including a first tubularaspiration member having a proximal end, a distal end, and a firstlength, the first tubular aspiration member configured to at leastpartially extend out of the lumen of the first elongate tubular memberat the distal end of the first elongate tubular member and into thevasculature of a first patient, a first elongate support member coupledto the first tubular aspiration member and extending between theproximal end of the first aspiration catheter and the proximal end ofthe first tubular aspiration member, the first elongate support memberhaving a first support member length, and a first annular sealing membercoupled to the first tubular aspiration member and having a firstdiameter configured to seal against the first diameter of the elongatetubular member, placing the first elongate tubular member into thevasculature of the first patient, placing the first aspiration catheterthrough the first elongate tubular member so that the distal end of thefirst tubular aspiration member extends from the distal end of the firstelongate tubular member and is adjacent a first target area and thefirst annular sealing member is aligned with the first diameter of thefirst elongate tubular member, coupling a first vacuum source to theproximal end of the first elongate tubular member so that materialadjacent the first target area is aspirated through the first tubularaspiration member and the first elongate tubular member, providing asecond elongate tubular member having a proximal end, a distal end, anda lumen extending from the proximal end to the distal end, the lumenhaving a second diameter adjacent the distal end, the second diametersubstantially the same as the first diameter of the first elongatetubular member, providing a second aspiration catheter having a proximalend and a distal end and configured to be inserted through the lumen ofthe second elongate tubular member, the second aspiration catheterincluding a second tubular aspiration member having a proximal end, adistal end, and a second length, substantially the same as the firstlength of the first tubular aspiration member, the second tubularaspiration member configured to at least partially extend out of thelumen of the second elongate tubular member at the distal end of thesecond elongate tubular member and into the vasculature of a secondpatient, a second elongate support member coupled to the second tubularaspiration member and extending between the proximal end of the secondaspiration catheter and the proximal end of the second tubularaspiration member, the second elongate support member having a secondsupport member length, substantially the same as the first supportmember length, a second annular sealing member coupled to the secondtubular aspiration member and having a second diameter configured toseal against the second diameter of the second elongate tubular member,placing the second elongate tubular member into the vasculature of thesecond patient, placing the second aspiration catheter through thesecond elongate tubular member so that the distal end of the secondtubular aspiration member extends from the distal end of the secondelongate tubular member and is adjacent a second target area and thesecond annular sealing member is aligned with the second diameter of thesecond elongate tubular member, and coupling a second vacuum source tothe proximal end of the second elongate tubular member so that materialadjacent the second target area is aspirated through the second tubularaspiration member and the second elongate tubular member.

Although several embodiments have been presented for breaking up orremoving thrombus, general aspiration (with or without high pressuresaline injection) of normal blood, or other liquids or deposits withinthe blood vessels, ducts or other tubular or non-tubular cavities of thebody is contemplated as being within the scope of the embodiments of thepresent invention.

While embodiments have been shown and described, various modificationsmay be made without departing from the scope of the inventive conceptsdisclosed herein.

What is claimed is:
 1. An aspiration system comprising: an elongatetubular member for insertion into the vasculature of a patient, theelongate tubular member having a proximal end, a distal end, a lumenextending from the proximal end to the distal end, and an inner surfacedefined by the lumen; an aspiration catheter having a proximal end and adistal end and configured to be inserted through the lumen of theelongate tubular member, the aspiration catheter comprising: a tubularaspiration member having a proximal end, a distal end, and a lumen, andconfigured to at least partially extend out of the lumen of the elongatetubular member at the distal end of the elongate tubular member and intothe vasculature of the patient; an elongate support member coupled tothe tubular aspiration member and extending between the proximal end ofthe aspiration catheter and the proximal end of the tubular aspirationmember; and an annular seal comprising at least one annular sealingmember coupled to the tubular aspiration member; a vacuum sourceconfigured for coupling to the proximal end of the elongate tubularmember; and wherein the at least one annular sealing member isconfigured to create a seal against the inner surface of the elongatetubular member, substantially preventing liquid having a viscosity ofabout 0.0025 Pascal-seconds from passing through an annular spacebetween the elongate tubular member and the tubular aspiration member ina distal to proximal direction and into the lumen of the elongatetubular member proximal to the at least one annular sealing member whena vacuum sufficient to cause aspiration of the liquid through the lumenof the tubular aspiration member and the lumen of the elongate tubularmember from the distal end of the tubular aspiration member to theproximal end of the elongate tubular member is actively applied to thelumen of the elongate tubular member at the proximal end of the elongatetubular member.